I went through this process exactly a few years ago. After a major breakdown (my third), my therapist kept telling me to change jobs, but I was too scared/depressed to make any sort of large change in my life.
After six months of weekly therapy, I finally felt well enough to hand in my notice. Once I'd done that I felt a huge weight lift off me. It still took several more months to get back on an even keel, and I'm still popping happy pills. The moral I guess here is... if people are telling you over and over again that your job is a major [bad] influence on your state of mind, then you should probably listen to them.
After six months of weekly therapy, I finally felt well enough to hand in my notice. Once I'd done that I felt a huge weight lift off me. It still took several more months to get back on an even keel, and I'm still popping happy pills. The moral I guess here is... if people are telling you over and over again that your job is a major [bad] influence on your state of mind, then you should probably listen to them.