Family gatherings were never too bad for me. I always felt a little uneasy at the Christmas parties where, I didn't always know everyone there.
Something I find useful is to stay up on the news any thing current so, I can start a topic or, be able to add to the conversation.
It's always best to be yourself. If, you're a decent human being and treat everyone with respect, people will like you for who you are. I try to remember, I'm no less important nor, any more important then anyone at a social gathering.
I do allow myself an exit plan to leave any gathering I really feel uncomfortable with. I'm lucky, my family gatherings aren't centered around drinking.
I'd of been thankful in the past when, I drank if, I could've gone anywhere and only had 3 drinks. You shouldn't be so hard on yourself for it!!