Christina Milian in Dog House

Lately R&B singer Christina Milian (real name: Christine Flores) must really feel it's "Us Against the World."

Milian is expecting her first child this month. However, her first "baby" - her dog - is causing her legal troubles. Her pet attacked Milian's 81-year-old neighbor and he's suing the songstress.

The suit was filed in Los Angeles County this month...