Hi - I can relate to what you're experiencing. I've been dealing with severe Depression since I was 14 years old (I'm 47 now).
You might to read "The Mood Cure" by Julia Ross. That book has good information on nutrition and supplements for depression. Jurplesman knows a lot about this--you might want to check out his old posts. He has some good articles on his website, and I can't remember the link.