Honestly? There is nothing we can tell you to do that will help make you feel better.
My birthday was yesterday, and this time 2 weeks ago I couldn't have cared less. I didn't have anyone I was particularly close with to share it with, didn't want to do anything, was depressed because school had been so damn stressful, et cetera. Just over a week and a half ago I fell into this amazing relationship. Literally fell into it, it came out of nowhere - and this was after 2 or 3 years of going through my own personal hell (with some occasional bright points).
As someone with depression, and who was suicidal as recently as a month ago, here is the best piece of advice I can give you: Keep on going, and at some point things will make a turn for the best. You won't know when to expect it, or what form it will come in; but when it happens, you will know.