School anxiety

I sit on a table and it's surrounded with people. They all talk to each other and the banter is flowing and I'm there. Theyre only sitting here because my other "friends" are. My hands start to go extremely sweaty and my face starts awkwardly twitching and I start to get really hot and I over analyse myself and my whole self image. I keep thinking to myself, I need to speak, what do I say? I want to be liked and accepted but I need to say something and I never do because I'm scared and anxious and I end up saying nothing because it's easier that way but it's not because I start losing friends and I feel so lonely because everyone is having a laugh and I'm zoned out and distract myself and I panic for the whole day and it exhausts me. I so badly want to leave this group situation but I am frozen and can't move. I just want to be normal, why am I like this? I would do anything to not be like this! Someone help me please x