I've dealt with things in the past, and unfortunately, the only one who can change this is you.
If you want to go places in the future, work hard in school.
If you want more jobs, apply to more places. You won't get great jobs at first, but the more experience you get, the better your resume will look.
If you don't like your body, then exercise more. Do something with your hair. Get a facial wash to start using.
If you feel like you want more serious relationships, go out and do something. Get active in your community, whether it's joining clubs, planning or going to festivals, going to concerts to meet someone with a similar musical interest, or going to a convention nearby for something you like.
I hate to tell you this, but you are the person who's going to have to change. If there's one thing that I can say prevented me from killing myself whenever I thought about it, it's that you don't know what the future will hold. You don't know what can happen, but if you kill yourself, you'll never know. In a literal sense, killing yourself is a waste of time. You were granted time on Earth alive, something very precious. Killing it after living only a quarter of your life seems like a pretty poor way to waste it all. I know things seem hopeless right now, but they can always get better, and you can always make them better, even if you think at the time that it won't make a difference.
Feel free to PM me if you ever need someone to talk to.