toomuch00, I agree with OOMIS.
First of all, the fact that you have friends is a big deal. For someone with social anxiety that is a huge step in the right direction so let your friends be a support system for you. Yes tell them what you are feeling and don’t be at all surprised if they are also feeling anxious about the Shabbaton.
Do you know what exactly you are feeling anxious about? Are you going to be spending Shabbos out of the area? In a hotel? In other people’s homes? Is it only about getting together for meals?
There are a lot of variables about such a event and there are a lot of reasons for feeling anxious. I am going to let you in on a little secret. When adults get invited for weekends simchas, we also feel anxious. Where are they going to put us up? What are our accommodations going to be like? Will we have a private bathroom? How far will we have to walk? Who else will be there? Who will they sit us with? What will everyone else be wearing? What should I bring? What if it rains? What if it is too hot? What if there is no air conditioning? What if the sky falls in……..
Doesn’t it sound silly? But we stress ourselves out about it also. So please tell your friends what you are going through and support each other through this. Make a plan such as you will pick each other up on the way Friday night so you know you will be together and the same Shabbos morning. Sit together in Shul, sit together at the meals or the lectures so you know you have someone to talk to and you won’t feel awkward. They will have your back and you will have theirs.
Hatzlocha, and don’t forget to breathe 🙂