I got five minutes on here and there is nothing I would like to do better than help a friend with those few minutes.
What I want ya' to do, Noke, is FORCE yourself to be happy. Some people don't think they can, and if they don't THINK they can, they obviously can't. I want you to freaking put yourself to the screws and tell yourself to be happy! The many times in my life I have even gotten to a depressed or angry state, I laugh out loud and then grin stupidly. It is a really, really, odd way of curing bad emotions compared to others, and some people don't think they can. If you can't the next best suggestion is what Kero suggested.
Oh yeah, and don't use vices of any sort; don't over-eat or do a single thing for extended time either. Do various things you love without suspending on one for too long, as that makes your thoughts linger. And, if you have expendable items that break happily, take a large blunt object and smash them, being sure that they don't make you regret it afterwards.
*Hugs tight and pats on the back* Everything is alright for you when YOU right everything, you know? Love ya' Noke!