'American Idol' alum Jax discusses her cancer battle: 'I'm running, I'm healthy and working out'

American Idol Season 14 alum Jax – who revealed this week that she has been battling thyroid cancer— has literally hit the ground running as she stares down the disease with a positive attitude and desire to get back to work.

Dressed in a leather jacket and enjoying a healthy dinner at The Gusto Grill in her hometown of East Brunswick, New Jersey, the 20-year old tells Billboard she is not letting a little thing like cancer get in the way of her goals. As a matter of fact, once dinner was over she was heading straight home to do a ten-mile run in preparation for the New York City Marathon on Nov. 6 on behalf of Tuesday's Children.

"I'm running, I'm healthy and working out," she says. "I'm also in the studio and getting back to a routine, which is why I thought now would be a good time to come out about everything because at first, I was not okay."

'American Idol' Alum Jax Battling Thyroid Cancer

Since she announced her condition on the air at NJ 101.5, Jax has been flooded with well wishes from fans, friends, family, and her extended American Idol family. Former judge Harry Connick Jr. reached out to check on her, as well as her season 14 friends, who already knew. Rayvon Owen, she said, has been a close confidant throughout the entire ordeal.

See photos of Jax on "American Idol":

"I called Rayvon immediately when I found out," she said. "He was like the only one I called at first."

Through it all, Jax has maintained a wicked sense of humor, joking that she is still radioactive from the iodine treatments, and her family keeps singing the chorus of "Radioactive" by Imagine Dragons to lighten the mood.

Her upbeat, can-do spirit is driving her to take on an insane schedule as she plans to independently release an EP in the fall.

"I hope people like it," she says. "I have a lot of empowering things to talk about after this whole experience."

BB: How are you feeling? You look great.

Jax: I feel good today. I'm getting a lot of love and support, which feels overwhelming. At first, I was not feeling okay, not looking okay, and just not doing okay. I wanted to be stable when I decided to tell people what was going on, and confident, and positive that everything was going to be okay, because I wasn't two months ago.

This all happened right before the Webster Hall show in April. It looked like you had a great crowd that night.

It was packed, and that felt so good because I was going through a lot before Webster Hall, simultaneously rehearsing and getting it done because we sold it out. I was rehearsing a lot out in Massachusetts and then I came in to New York to wrap everything up and get ready for the show. In the meantime, they were testing me, bringing me through ultrasounds, thyroid specialists, and testing for Hashimoto's Disease. They performed a biopsy on me, and then I did the show. Afterwards, I was waiting for the results but I wasn't even thinking about it. And then a few days later all the test results came back positive. It was crazy.

When you were first feeling sick, you visited urgent care, right?

Yeah, Brunswick Urgent Care! Shout Out! It was funny because I went back, my little brother he was at Ellis Island in boot camp training for the Marines. He split his knee in training, so we were all urgent care ready. I went back for the first time since surgery, and they were like "Oh, Jax you were here before! We diagnosed you with that, that sinus infection!" And I was like, "oh, no it was cancer. You were a little off with the diagnosis." But at least they gave me a prescription, and they didn't let it go. If you're worried, which my mom was, (they said) "here's the ultrasound. Let's do it." So we did. I guess they were part of the process. And they definitively guided us through Hashimotos, which explains the state of mind I was in.

'American Idol' Alum Jax Addresses 'Sometimes Bitter' TV Experience in 'La La Land' Video: Watch

You were out in Los Angeles before any of this happened. You were out there hiking up mountains.

I was in L.A. doing press for "La La Land" and recording. I was climbing mountains with (American Idol Season 9 alum) Didi Benami. I was doing everything out there, and it was just a lot. But I was not myself. It took a lot every day for me to kind of just wake up every morning and start my day. I was in a really dark, dark place. Every day I'd have to get up, call my parents and have an emotional breakdown on the phone, and then start my day. It was like part of my day. I was crying, you know it was a lot of pressure, and the business takes its toll on you, especially when it's the first time I was on my own, on the West Coast, thousands of miles away from home. I mean I've always been in the business, but after being in the spotlight and doing the American Idol tour, and just having that platform and going back into the real world, out of the bubble, it's like shocking.

Slash from Guns N' Roses had the best analogy about that. He said when you get off tour, it's like wind and tumbleweeds.

Honestly, it's a thousand percent true. That's what it feels like, especially the hype, which is insane. It wasn't so much coming down from the hype, it was almost like me, Nick (Fradiani) and Rayvon were really close on tour, and then all of a sudden you're kind of divided from your friends, and these guys are my family. Especially Nick. He's like my best friend. For a straight year we're so close and all of a sudden we're off doing our own things. No one knows me the way these kids know me. I have my family but I'm thousands of miles away from them, and it's just a lot, L.A. is a tough world, and I was not happy. But it wasn't the usual not happy, because I'm usually good under pressure. I've always been a hard worker, always been so committed to everything, but I was just going through the motions, it just felt like there was a weight on me and my parents were like, "something is weird". It's hard to separate from both a physical and emotional standpoint and what was just because of the last two years of my life, and what was new and not right. Emotionally I was sick, but it could've been from the show or the tour. It could've been the music business, or it could've been something really wrong with me. And my parents didn't know if it was just part of the grieving process, or was it something else.

Did they think about getting you a therapist?

I did. I went to therapy. I was on medication, and nothing seemed right. My body was acting wacky.

So you figured it was something else.

Well yeah, but I'm the kind of person who likes to "whatever" everything, and be like, "no that's cool, I'm young, it's whatever." I remember there was one time Nick and I were getting each other sick back and forth. It was after tour and I was in L.A. and there's a club called Warwick, and all my friends were going for a birthday party and they were like, "Jax come on come on let's go!" I was ready, and Nick is like, "dude you're really sick". And I was like "no, I'm cool," and maybe if I just say I'm good enough I'll get better. And I go to this club and I'm there, and I feel dizzy and about to pass out. I couldn't breathe through my nose. I come home the day after, go to the doctor, and they're like holy crap you have serious pneumonia. You're really sick and need to go get x-rays on your chest. How are you walking right now?

When was this?

This is after tour. I have this super weak immune system. My mom is a school teacher, so she gets sick like once every five years. But me? I get sick every week. I didn't take how I was feeling seriously, and there were times where I was like throwing up in L.A., and puking blood and at one point everyone was like something seems off with that. Either you're severely dehydrated or something's wrong with your organs. It wasn't because I was partying or anything. Anyway, we came home for this Webster Hall show and I got checked out, did the ultra sound, and it turns out I have 18 tumors in my thyroid, which would explain everything I was going through. There weren't many symptoms for cancer, but this Hashimoto's Disease -- people don't realize how important your thyroid actually is -- it is the center of your body and your hormones. I was waking up tired, and I didn't have energy for anything, I was losing weight and gaining weight. It was completely fluctuating, and everything was off. Every step felt like a 50 pound weight on my foot. Hashimoto's affects your immune system. It affected everything, and every mood swing I had. It wasn't normal, the way I was having breakdowns.

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That explains why you weren't at the American Idol finale.

I was not feeling it that day. That week was a hard week. I had a couple of appointments with the specialist, and they were like yeah you have to go gluten free, and we'll put you on medication. And then they said as a precautionary thing, you should go biopsy the tumors on your neck to make sure they're benign and not cancerous. They sent me to the surgeon, and it took a while to book that appointment because he's a really good guy. And he did a needle biopsy on my neck, and 12 out of 18 of them turned out to be cancer. I realized that after the Webster Hall show, which was such a painful show for me. I'm shocked it got good reviews because I was almost crying afterwards. I was like "something's wrong guys," like I feel like I can't breathe everything's burning here, it was really painful to sing. I was sick already.

You had surgery soon afterwards, right?

A few days later they were like "yeah it's all cancerous and we need to remove your thyroid, like now." Sometimes they want to preserve it because it's so important, so they'll only take out half of a lot of people, but mine was everywhere, so they took the whole thing out. They took it out pretty quickly after that. I called Rayvon immediately when I found out. They threw me right into surgery. It was shocking. My parents waited a day before they told me, they wanted to know how to go about it. My mom was hysterical.

Your parents are lovely people.

They're the best. They did not deserve to go through this. I put them through the ringer in this business, and it was so crazy, but it was a wakeup call. I needed to be home. I needed to take a break and breathe for my own sanity and my body, and my mind, everything.

That's so scary as a singer.

One hundred percent. My grandfather had it, and he had his thyroid removed, and now he can't talk permanently. This was two years ago. So when we found out we had to do the surgery and take it all out, we went into full panic. So my mom did some serious investigation in finding the best surgeon she could, and the surgery actually ended up doubling in time. It was supposed to take a short amount of time. It was a simple process, but the Hashimoto's inflamed everything, and the vocal cords lie right on top of the thyroid. So in order to get the thyroid out you have to go invade the vocal chords.

Did they put a tube down your throat?

Yeah, and that was the worst thing for my vocal cords. The tube is the most damaging part of the whole thing, for so many hours having that thing in your body. And it lasts forever. The effects of that could last for over a year.

So you're a little raspy from it?

Yeah, I'm raspy, I don't really notice it but a lot of people have been saying it. Katherine Winston was my roommate on Idol, and we would get sick, so we'd sound really raspy and we were like "oh, could be worse. I mean, we sound kind of hot".

You should be resting, but you aren't. On the radio the other day you listed all of these places you are going in the next month. What is the plan?

I need to stay active. I'll be writing a lot in L.A. I'm completely booked, almost. I'm leaving on the 17th to fly to L.A. until the end of the month. Then I'm going from there to Nashville for like a few days, just to meet with people and have a few meetings out there. Then I come back home around the 3rd or 4th of September. And then I go from there to Chicago, first week of September to do a charity gig. Then I go to Jacksonville, do another charity gig, then Miami and another charity gig. Then I will come home, and go to South Carolina for my brother to watch him graduate boot camp. Then I'll spend the first week of October in London for writing, and by that time I should have everything together as far as music goes. After that, I have two weeks to prep for the marathon.

How are you going to train?

I'm just going to do it.