JonB, I finally got to the point when my family knows exactly what I need. I try really hard not to be selfish on my need of spaces and "please not so much noise"; I think I try to set my mind on a between moods mode.
It's not easy but I don't want to spoil the party and at the same time I want to enjoy.
My siblings and I talked about meeting in somebody else's house, because I also have OCD so it's really easy for me to start obsessing about every little thing people do while in my house.
I'm going to my sister's and when I'm ready to go home, I just do. Usually during the party time I go outside or to the bathroom just to have some space and fresh air.
If you know what triggers you it's easier to prevent a bad moment. I'd suggets you look at your own patterns and you will find, eventually, a way to deal.
In the meantime, hang in there, and if you want I can take one more beer outside for you, lol!
Good luck!