Were you or are you still on pain meds from the back surgery? In 06 I had a bulging disc which I had surgery for, when I weaned from the pain meds I became very depressed to the verge of sui. I have since discovered that codeine triggers mood swings. ( I went hypo 2 other times since then) My pdoc at the time talked to me about it and said if I ever needed surgery again we would increase my mood stabilizer to compensate. Anyway I hope things get better soon.