You were anxious (lack of a better word) on making a good impression on meeting a group of people that are important to someone that's important to you. I think most people are like this when meeting a new bf/gf group of friends. It's pretty natural to want to be accepted and fit it. You had a lot of alcohol in a short period of time to calm nerves/keep up with the group. This is also very common, at least in my experience! The combo of nerves/alcohol can and more likely than not, backfire. I've had it happen to me, my friends and family.
The good news is you got out of the situation and no one but your so saw your breakdown when it happened. My guess is your bf was irritated partially because you were assuming it was a bigger deal to his friends that it was.
If they are the type of people to judge you so harshly after such a short interaction then you need to decide if such people are worth getting so upset over.

Edit to add- I reread your post and replies and it seems you are very much aware of everything I said. If it makes you feel better to know, yes this does happen to others! My brother (along with everyone else in our family) has massive horrible anxiety. He was invited to my very social husbands stag party before our wedding. It was a weekend deal and lots of alcohol. All I heard afterwards was what a *** my brother was, even earning a nickname for himself! I really felt so bad as I knew he was on edge and acted poorly bc of it/alcohol. I know he was so ashamed and probably didn't want to go to my wedding 2 weeks later and face people. He went and it was fine. No one even brought up anything to him to his relief!