Most Helpful Guy
First off, I would not hang around such negative influences. I don't know if they are more athletic, smarter, what have you, but at least you can say you have nicer personality than them.
Second, we can't be perfect at everything. Jerks like them will always try and find whatever you are worst at to try and make themselves feel better. Once you find something that is your passion though, like something that you are better at than most people, attention will be shifted to how awesome you are that than all the negative things.
I used to take when people said insults to me really hard. Like self-esteem would drop hard from them. Now I realize though that their words can't change crap, and all them trying to show me how horrible of a person I am just makes them look petty.
If these people are "friends" that you want to keep, I suggest talking to them first. Tell them what you wrote on here, and if they are friends worth keeping, they'll change.
That being said, there are always people in life that are total assholes and will insult you in worst ways possible. It is important to realize they are indeed assholes, and don't let them get to you.
Most Helpful Girl
I think if you show them that you are Confident enough to stand up for yourself that they will have Respect for you and learn To... Shut their lion's mouths.
They are mistaking your kindness for weakness and this is why they feel they can open up harshly when they feel like it. They use you as a scapegoat to ridicule you and when you let them get away with it, they keep on doing it. It gives them satisfaction in Feeling like a straw boss.
Show them they are rude and crude and start to begin a new beguine of being a bit rude and crude to them and see how they like this New sheriff in town.
You will feel better in no time when you put them in line.
Good luck. xx