Why do my "friends" make fun of me so much?

If I were you, I would talk to them about it. Maybe the next time they're making fun of you, you can tell them that you don't like it and that it pisses you off. If they continue doing it, then they're not worth a minute of your time. You can find friends who won't treat you like crap. And punching any of them is probably the worst idea. Just talk to them, maybe ask them to stop.