I have very bad social anxiety.

Hello!
this is my first time on here, its nice to meet all y'all. I just want to rant about smth I've been struggling with. Being social with others. This is smth I've always had since I was 8 years old. In elementary school I was a very weird yet quiet kid. I always wanted to fit in with the kids that were cooler and more popular. I did hella weird stuff. Like eating crayons, eating paper, etc. I do any dare just to be part of their group, but all they did was just make fun of me for my hairy arms, for my quietness and my weird interests. Anyways, that's my backstory. So in the present day I still have social anxiety. It's gotten so bad that I cannot even talk to my cousins that I see every day. I maybe talk to one that I gotten comfy with but overall non of them I am close with. Sadly, I dont get invited to a lot of outings with them because of my parents. They always say no. I remember this one time my parents let me finally meet my cousins friends at a restaurant for a bday celebration. And I was so awkward. I did not talk to them that much my cousins talk to them a lot since they are close which I understand. And I was just so anxious the whole time I was their because 1 my parents kept blowing up my phone asking where I am and all that and 2 I was just scared of what happens when I get home from dinner. Will they hit me? will they yell at me? will I never be able to hang out with them? my mind was going crazy. And I had to leave early because my parents like I said kept blowing up my phone and since my only ride was my cousins they had to also leave. And I could tell that they were annoyed. They ranted about me needing to stand up for myself and I do a lot of the times but I just get hit as a result. I felt so ashamed of not only making my cousins leave early but my parents blowing up my phone. And now ever since then I have never been invited to any outing..I just wish I had friends. I am not even allowed to have friends. Im not sure what do I do. I try to practice talking more confident for months and that never helped. What can I do to fix this?