I'm sorry to hear that you're feeling so alienated @Ballerina_ that is so hard. I think it's quite normal to feel angry in response to this kind of thing - anger is a secondary emotion that often arises as a result of feeling hurt, and feeling like you're on the outside really does hurt.
Sometimes it can help to remember that most people do struggle with social anxiety from time to time, some more than others. We might see others having a seemingly easy time connecting to people but what we don't see is that inside they are also feeling quite anxious. What sort of things are happening that feels like you're being pushed out?
Is there a particular person you feel closer with? It could be worth talking to them about how you feel - sometimes the best way to deal with anxiety is to name it, and if the friend is a good one, they could reassure you and make an effort to include you more. Just a thought anyway.
You can have a read through some of our resources about this stuff, might be helpful -
How to make friends at school
Meeting new people
A gazillion ways to make new friends
Social anxiety
