I tend to get depressed from time to time, but I think it's hormones. I think it's perfectly normal to mourn the loss of a relationship. The problem is when the mourning period should be over and you seem to be stuck there. You know you just have to wait it out, so you wait...and wait.

Bagpuss sounds like a professional. In any case, she(?) makes perfect sense. Much of what goes on is chemical, but I don't believe we have absolutely NO control, but how much depends on each individual. Excercise does help, even if it's just going out for a walk. Talking with people - well, you're not alone, are you? I tend to feel worse when there are no distractions and I can crawl up me own arse in peace. If I do have distractions, I usually don't have the time or attention span to dwell on how miserable I am. Of course, this only helps if the depression isn't bad enough to completely immobilise you.

I also think some form of therapy (what's 'cognitive therapy'?) might be beneficial - not just to get you out of this episode, but perhaps help prevent or minimize future episodes. Might just give you some mental tools to help fight the beast.