Anyone have any suggestions for surviving large social events after a loss?

We experienced a later loss several months ago (23 weeks, TFMR) and I am still having a tough time. My coping mechanism has been to withdraw from social obligations - I've always been fairly introverted and I feel most comfortable right now being by myself (without the pressure of having to put on a happy face for others).

We have a family wedding coming up, and I'm DREADING it. It will be big and loud, at least 300 people. To make things more painful, we recently found out DH's closest childhood friend's wife is pregnant with their second, and that news was shared with us in a *really* insensitive way.

DS is a ring bearer so I have to go, otherwise I would send my regrets. I'm dreading having to fake it around so many people, and I'm really dreading interacting with the couple who is expecting (I know that's not fair, but neither is loss, right?).

Other than taking FULL advantage of the open bar, how to do I make it through?!?!