Mish, didn't you just get to go to 2 live concerts recently? And had a BLAST?! Go back and read those posts again - print them out. Make a gratitude journal, even when you don't feel like it. Even if you are struggling to think of anything. When we get depressed and start to "spin," those thoughts reinforce themselves and only magnify. It's the whole concept behind The Secret - it isn't a secret! By focusing on the negative, you start to look at everything in a negative light, even things that made you happy (or you just "forget" them completely).
Focus on the good - there is some, more than you want to recognize right now.
And that is coming from someone who, on occasion, just needs to wallow in her own mess from time to time.