I'd start with looking into CBT, aka recognizing and taking negative thoughts, and turning them around to be positive and beneficial in some way. Look into getting a T who will do this with you, or find a book online about it. Either way, the sooner you start rewiring your brain to look at the glass half full, the better you'll feel in the long run.

Now, I'm not saying it's a cure all, but it does help more than you'd think.