My friends are keeping me from new people

they shouldn't be getting jealous because you want more friends in your inner circle. Talk to them, explain to them that you're not trying to replace them or ditch them. You just want more people to hang out with. That's most likely why they're becoming jealous

if people are gonna keep you exclusive, maybe try to explain that they aren't your third set of parents and that you're an individual who wants to experience what various people have to offer

These people only have as much power over you as you allow them to have. Their anger is intangible; being angry at you can make you feel bad, but it can not hurt you. Do not be afraid of someone being mad at you.

Go to school and talk to someone new and when your "friends" try to peer-pressure you out of talking to them, assert that you are not in a power clique; you will make friends outside of the cloister if you please, and assert that if they can not accept that then they are not your friends, they are a group of abusers pretending to be friends.