Ok op breath and start thinking rationally, beer fear is making you feel worse.
Firstly, let this be a wake up call to you that you never ever touch vodka again. Just don't go there. And also no alcohol is going to help your anxiety.
You are 23, I think most people would be lying to say they didn't get ridiculously drunk at your age and do something they regret, I definitely have.
There is nothing you can do to change it now but how you handle it is going to determine so much for you now. You also can't control if he dumps you or not but again how you handle things now will make both of you feel some bit better regardless of the outcome.
I would contact your bf, apologise, pledge never to drink to that excess or touch vodka again. Tell him you want to stay together but understand if he doesn't or needs time and then leave him be.
I would contact his family and apologise, say you understand, you don't expect forgiveness but nevertheless wanted to apologise and wish them well. Put on your big girl pants, if that was me I would respect the fact you faced me and apologised, I might think "she's a totally idiot but at least she braved it out and faced me". It may not change anything but if you live in a small town it definitely won't hurt.
I got very drunk and called my mil a bitch, to be fair I had every right to as she was being one but things are fine now