Demi Lovato struggled with body image months before apparent drug overdose, source says

Demi Lovato was putting "added pressure on herself" in the months leading up to her apparent drug overdose, a source tells ET.

The 25-year-old singer, who had been traveling as part of her Tell Me You Love Me tour, was concerned about "looking great" for her performances, according to the source, who adds that Lovato was "feeling self conscious" about her weight.

"Three weeks ago, a close friend of Demi's tried to sit down and talk to her. They were so worried," the source says of the singer's relapse after six years of sobriety. "They wanted to help her slow down and live a cleaner lifestyle, but all she cared about was her weight gain."

"She didn't want to talk about her drug or alcohol use, she wanted to discuss dieting. Demi started gaining weight in the last few months and her friends knew she was partying way too much and was in a terrible place," the source claims. "Demi is very self-conscious about her weight and she puts added pressure on herself to look great because she feels that it's what the public and her fans expect, but she wasn't willing to give up partying for weight loss."

And according to our source, those closest to Lovato "saw this OD coming." An additional source told ET earlier this week that Lovato's family is already looking into rehab facilities in hopes of checking her in right away.

"Her family is going to do everything in their power to help get Demi back on track and are making plans to get her straight into rehab," the source said. "She is a fighter and has beat this in the past, so they know she can live a clean and sober life again. Her mother is by her side."

Lovato first entered rehab at the age of 18, completing her inpatient treatment for "emotional and physical issues" in January 2011. She later revealed in various interviews and in her documentary, Simply Complicated, that she struggled with bulimia and was self-medicating with drugs like cocaine and alcohol.

Since her treatment, she's been very vocal about her past struggles with sobriety, substance abuse, self-harm and body image. Back in January, she revealed via Twitter that she had gained a little weight.

"Feeling gross today at a photo shoot but I'm choosing to accept what I see because I love myself for who I am and your love and support gets me through moments like this," she tweeted at the time. "If you're struggling as well, don’t forget.. if I can do it, you can too!"

"No longer depriving myself of treats (in moderation) and I'm not gonna lie, I put on a couple lbs since I've given up dieting," she continued. "BUT I've given up the chronic stress of what I eat because I don't want to set that example for my fans. No more food shaming myself!!"

As ET previously reported, a source told ET on Tuesday that Lovato was stable, and "awake and responsive" following her hospitalization. Her rep also released the following statement:

"Demi is awake and with her family, who want to express thanks to everyone for the love, prayers and support. Some of the information being reported is incorrect and they respectfully ask for privacy and not speculation as her health and recovery is the most important thing right now."

If you or someone you know is struggling with substance abuse, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-HELP (4357).