How are you filling out your resume? Leave off any mention of mental illness. Put as positive a spin on it as you possible can. "I was having a little medical problem during that period, but have it under control now." You may have to start at the bottom and work your way up again to get yourself out of this mess. Even if it is beneath you, there are always places like walmart that are hiring, and it will give you a chance to rebuild your resume. You may need to prove you won't walk out on yet another job before you can get into the higher paying ones again.

There is always the option of temping, if you don't feel you can handle full time without walking out. That will give you a solid looking job period, without actually working a 40 every week. It will also give you a chance to build up positive references to use instead of your old jobs. Worth a thought.