I lost my last two jobs due to missed time due to depression. My doc did give me some paid state disability time but was very stingy with it compared to my mental state. I can't really blame the company as they were under tremendous pressure to meet deadlines. I had doctors notes but didn't pursue anything.

There is the family medical leave act.

http://www.dol.gov/whd/fmla/

I believe you have to be at the job for a year. They cannot fire you and have to keep your insurance in place if you have it. Not sure of what it takes to qualify but worth reading up on.

Does your state have a disability insurance program that you pay into similar to unemployment. I know CA does. If you were on that I doubt they would fire you.