being a teenager sucks. some of this is just because you're young... I know you might resent that answer, but it's just true.<br />
The only thing you can really do is try to focus on others, on helping them or being the best person you can be. Sometimes just a shift in orientation (away from your own stuff and towards helping someone else) can make problems seem so much smaller.
I'd say it's because you're smarter than them.
sometimes you can have a lot of friends, but still feel alone; maybe you don't have the kind of close friends where you feel validated; also, maybe you're searching for something that your friends can't help you find.