Body chemistry is important, but the most effective measure (exercise) is also affected by cycles: sometimes I exercise for months, sometimes I don't move a finger for months. It's easier to take care of what I eat/drink/smoke, at least for me.
The other thing that works is routine. But not trying to control every thing I do or I don't. Working on something or writing, learning English, playing the guitar regularly, even half an hour a day results in progress. Progress makes confidence.
And solid confidence is the best thing to lean on.
Hope it helps.
I have, unfortunately, never discovered a solution. If you figure it out, remember to share.
I ended up not really going to see anyone, though. The one time I did see someone, I happened to not really be that depressed at the time, and so he seemed to think that there wasn't much wrong with me, but I wasn't sure I could trust his opinion since I don't think I could effectively relay how I feel when I am depressed to him. I'm going to try and push myself to actually go see someone again, though. Hopefully I'll be able to explain myself better, or at least see someone frequently enough that eventually my feelings will come out.
You might print out your posting and bring it in.
feel free to contact me if you wanna talk.
it gets better.
oliver@olivernowak.com