First of all, I want to say congrats on your soberity and welcome to SR!
I'd like to suggest taking a friend who is also in Recovery, a Sponsor, if you go to meetings or at least someone with a fair amt. of clean time to be supportive of you. Most Family get togethers don't mind someone either bringing a date, spouse and or a friend. It helped me my first few social gatherings where I knew alcohol would be flowing, to have someone with me who didn't drink and knew my circumstances.
I think taking your own car, or the friend's car is a great idea. Perhaps you could let a few people know not too long after you get there that if you leave a little early, it's not that you don't want to be there, but you weren't feeling good earlier in the day. This way, if you have to bow out early, no one would be surprised or offended. You still made your appearance but have an easy out if need be.
Sometimes we may have to tell a little fib in order to protect our Sobriety that we've worked so hard for. I think our HP would forgive us for something like this. I think you'll be just fine!
God Bless,
Judy