I'm impressed, Tosspot. I should find my own depression mantras. I only really have one, which I use if I'm in lecture and can't pay attention because of the psychological pain/fatigue/cognitive symptoms. I write "I am stronger than depression" somewhere in my notes. Sometimes I need to write it multiple times. :P And I can relate to feeling like everything positive was a delusion. This applies especially to everything positive I've ever felt about myself.

Confused, you have an interesting view of it. I think it's probably a good thing that you look for external causes; even if there really wasn't one, feeling like you have an explanation might make you feel like you have more control. I'm glad that you haven't SI'd, but sorry that you've had strong urges. Are the "negative voices" hallucinations? I've read that a lot of severely depressed people have auditory hallucinations of voices telling them that they are worthless. It's never happened to me, and I'm glad; it sounds really scary!