Due to covid and then going to university, I haven't gone to a big (meaning &gt;20 people) birthday party in 2 years. I have gone out with people to a bar or even a club-like scene, maybe a chill bbq as well, but obviously you do not really get personally invited for those things as they were organized by our faculty/uni. Also, most people attending those events do not (really) know you.

Two weeks ago I was added to chat for a birthday party of a new friend, saw the 25 (un)known numbers and I was looking forward to getting to know people (better)! but dayum, the table have definitely tabled.

1st hour was just fine. Daylight, chill conversations, quiet music. 
2nd hour was okay, too. Food, lively conversations, slightly louder music.
Then the music got louder, people were getting drunk and they chanted loudly to the songs. Conversations couldn't really be held in a normal voice as well. Did mention everything happened in a party tent?

I realised back in the day, people only invited me to big parties bc they wanted their party to be big. And when I was there, you could be sure someone else wasn't really keen on being present as well so you could look for an unused room and talk somehow normally, rarely disturbed my drunk friends. I couldn't really do that yesterday.

I was sitting between people who didn't really know how I react to parties like those (I also only then realised/remembered that I do not take those events lightly). I became so mentally tired, J couldn't hold my head straight. I constantly supported it with my hands and arms and really wanted to sleep forever, most optimal fall into a dreamless coma.   Some people were asking whether I'm okay and I couldn't really get one thought straight and sometimes replied with nonsense or not even anything at all bc my mimics apperently spoke for themselves. When people were talking about me or tried to get me into a conversation, the amount of eyes unsettled me tremendously and I wanted to leave ASAP. Especially then, my mouth was blocked and I couldn't say anything. At some point, I had the strong urge to leave and went for a 30min walk all by myself, knowing that if I would come back at some point, people might see my and call my name, meaning even more eyes would be fixed on me for a moment. But I really wanted to leave and so I did. I only told one close friend because I didn't want anyone else's attention again on my condition and many people had already asked whether I'm okay (to which I kept replying "i don't know, but it's ok").Once I left the grounds and the music grew more distant, I felt such a relief from it that I wanted to run away from the noise until it's totally gone. I didn't run then, but I went away far enough to not hear the party anymore. 

After I was called because people became concerned, I went back. Luckily no one really noticed so I just sat back onto a table with a few people and rested my head on my arms again. I do not know what happened in the following two hours because I must've been too tired to remember.

What striked my the most was people saying "I'm looking forward partying with you once you're feeling better" but I have the feeling I will often react this way, if not every time. I was wondering whether I could call this some sort of anxiety or just exhaustion (I have been to 3, uni-organized events this week with &gt;20 people, but those went rather anonymous)... Or both. Maybe I was just overwhelmed?

Has anyone else made a similar experience? I'll put this in the anxiety subreddit because I do believe it's somehow fitting. I might be wrong though...