Just gonna throw my $0.02 in as well.
I don't have half the experience that some of the guys here have, I'm only 18 after all, but I've been through some tough shit myself.
Up until I was about 14, I was the kid in school who didn't really have any friends. I hung around with this group who didn't really like me, they used to pick on me and stuff and they didn't talk to me, y'know. Then one day I figured I'd had enough. I walked away and spent every moment of free time by myself, I promised I wouldn't go back to them no matter what.
Anyway, to cut a long story short, I met a girl and fell in love. She loved me too but we couldn't get together cos she couldn't leave her psycho bf, and I got fucked over for 2 years. I was headed for a mental breakdown - I nearly did go crazy because of it and I was lucky that she left.
So I reformed again. I became massively more confident around everyone and everything, after all, nothing could possibly hurt me as much as what had happened. I'm now much happier and probably the only popular kid I know who has no enemies. I can take the fucking world on.
The point to this story has already been expressed (much better) in other posts. You can turn your life around, no matter where you are, no matter how low, no matter what, you can go from the bottom to the top.
My idol in life is Frank Sinatra. I love his music for one thing, but even if you don't, some of his life can really be inspiring. He was probably the most popular singer in America in the 40s, and then in the early 50s - his career plumeted, he'd left his family for a wife who didn't love him, he was abandoned by all his labels, his voice was haemorraging, he was trying to kill himself, he was down to 120lb, he was a total wreck.
But he landed a role in a movie he was perfect for, won an Oscar, and blasted back to the top of his form. Having hit rock bottom, his work had 5 times the power and emotion, the public adored him again, he was a superstar.
Plus Sinatra was hung like a fucking horse. No kidding.
Red, we're with you brother