iv in the last week or so come out of a long spell of depression - and i have some advice
1. dont be by yourself - hang around with your friends - even if you dont tell them about your problems you will feel better. if your friends arent about, hang around with your family. if they arent about, sign up to a beginner class in whatever interests you and meet new people
2. get busy. this helped me ALOT. even though you might not feel you have the energy or the will to do something - put some serious effort into something. the gym, reading that book you never get around to, learning a language. if it seems hard, thats because its worth doing.
remember you arent alone - if you are feeling shitty tell us about it. we will listen (or read, but you get the idea)