That sounds very similar to how 12 step meetings were for me for a long time.

Arriving early so I would have time for everyone inside to adjust and calm down really helped.Allowing time to know the place,where exits were,where the bathroom was,where literature was kept,etc.helped to feel safer and eased some anxiety.Plus,arriving early meant I got to find a seat I thought would make me the most comfortable,usually in the back corner so there was nobody behind me and I could see the entire room and getting there early I didn't have to walk into a room that was already full of people that would be watching me.I stayed a little late too,leaving after everyone else did instead of running out the door as soon as it was over like I did at first,it helped build my tolerance for being there or something because I 'could' have ran out the door but by staying I was showing myself(selves) it was ok to be there.

It was really hard to share though and when it would be my turn I would panic or dissociate at first.One night when it was my turn I just said "I struggle with severe anxiety and I am so nervous right now and I might have a panic attack,but I'm going to try my best to talk anyway".Everyone understands anxiety,so if I did say or do anything out of the ordinary it would just be assumed it was from that.Just saying what I did really helped,instead of really worrying about what I would say or do and how I would look to others,what they would think of me,saying I struggle with severe anxiety took away the anxiety over it.

Another thing I did was take a small comfort object with me,something small enough to keep in my hand or my pocket and I would touch or rub it as much as I could.Nobody even noticed what I was doing.

Things did get easier the more I went.Keep going,it will get easier for you too.Maybe you should try to find things you can do to that will make you feel more safe and calm.