AITA for being upset with my best friend who ruined my birthday party? So, this past weekend was my 24th birthday, and I was really looking forward to celebrating with a small get-together at my apartment building's party room. I invited 10 friends, got some nice snacks, wine, non-alcoholic drinks, and a cake. I always have a blast at these kinds of gatherings. My best friend, "S" (23F), who I've been close with for 7 years, told me beforehand she'd be a little late because she was at a graduation barbecue for another friend. Totally fine by me (24F, ADHD, perpetually late myself!). But she ended up arriving two hours late, and she was already quite drunk. Initially, I didn't make a big deal out of it, especially since some of us were drinking anyway. However, S kept going. She got really loud, and a few of us, including me, suggested she eat something and drink some water to sober up. Later, we started playing party games, and S, who is super competitive and a terrible loser even when sober, was losing. Being drunk just amplified this. She kept drinking despite us asking her to slow down, and her behavior was honestly embarrassing. She was getting aggressive with the people who were winning, and our mutual friends kept telling her to chill out. I told her again that maybe she should stop drinking, and offered for her to sleep at my place so she wouldn't have to go home in that state. She replied by saying she'd only sleep over if we spooned, which felt like a weird and inappropriate comment, especially in front of everyone. For context, there were a few different groups of friends at the party. Two other high school friends and their boyfriends were there, along with two friends I've made through my boyfriend, "J." It was the first time one of the boyfriends was meeting everyone, and the first time my high school friends were meeting my boyfriend's friends. So, S was acting this way in front of three people who were essentially strangers to her. At one point during a game, S actually bit me on the arm. Like, a full-on bite. It hurt, and I had a huge bruise for two weeks! (A professor at uni even asked if everything was okay at home because of it). I went to the kitchen to grab a cold soda from the freezer to put on my arm. When I came back to the party room, S tried to snatch the can from me, wanting to drink it herself. I was already annoyed and told her to get her own from the kitchen since I was using this for my injury. She didn't seem to register that she had hurt me. She went into the kitchen, and not two minutes later, she screamed my name. She had somehow cut her finger quite badly on the sharp opening of a soda can – apparently, she decided sticking her finger inside was a good idea while drunk. There was a lot of blood for a finger cut, and I got worried. She started crying, and since it was past midnight, my other friend "B" and I took her to my apartment to get a band-aid, holding her hand because she was so out of it. She was being incredibly loud in the hallway, and I kept asking her to be quiet because of my neighbors and thin walls. When we got to my door, I realized I didn't have my keys. I asked B to stay with S while I went to get them. I was gone for maybe five minutes, but when I got back to the elevator, S was there, crying again and looking furious. When I asked what was going on, she refused to tell me and said she was going back to the party (which was definitely winding down at this point, with everyone feeling awkward). I told her there was no party to go back to, and she said she was going home. I insisted she wasn't going anywhere alone in that state and pressed her to tell me what happened. Finally, she admitted that my next-door neighbor had asked her to be quiet – which is completely reasonable since the neighbor has to work early on Sundays. S's brilliant response was to storm off, intending to go back to the party and say something classist to my neighbor along the lines of, "Who is so f***ing broke that needs to work on a Sunday morning?!" At this point, I was beyond frustrated and exhausted. I told S she could either go home with our other friend "L" (who doesn't drink and had offered to take her) or sleep at my apartment. This whole exchange was happening with her half in the elevator, throwing a tantrum. She said she'd go with L. When we got back to the party room, she suddenly declared she was going to Uber home alone. I was so done with the drama, but I absolutely wasn't going to let her do that in her condition. L stepped in and firmly told S that she was going home with her now, and if she didn't, their friendship was over because S was being inconvenient, embarrassing, and putting herself at risk. S started crying again but finally agreed. She gave me a quick kiss goodbye and left with L and L's boyfriend, "C." Everyone else was pretty uncomfortable. I tried to lighten the mood by suggesting we have cake since we hadn't even sung happy birthday yet. We did that, took some pictures, and after everyone had some cake and took some to go, they all said their goodbyes. My boyfriend and I cleaned up, and I just went to bed, completely drained. The next morning, I left a note and some cake for my neighbor, apologizing for the disruption. I spent Sunday trying to process everything. I was honestly more worried about S than angry at that point. This wasn't the first time she'd gotten really drunk and needed help, but it was definitely the worst. She sent a general apology in our group chat and a private one to me, but it was very vague. When I asked her if she remembered what happened, she only recalled getting to the party and leaving with L. So, I filled her in on everything. She said sorry a bunch more, and I told her it was okay, that I was worried about her drinking and her memory loss. I thought I was okay with it because she had apologized and seemed embarrassed. But on Monday morning, when I realized my mom was coming to visit on Wednesday, I knew I'd have to explain the huge bruise on my arm. I sent S a picture and asked her to send me a voice message for my mom explaining that she bit me, to avoid my mom thinking it was something else (because a big bruise on a young woman often leads to those kinds of assumptions). S apologized again and sent the voice message. When my mom saw the bruise, she immediately believed my explanation but then said something that stuck with me: "Well, it seems like S doesn't like seeing you too happy." As time has passed, I've realized I'm not okay. I feel hurt, but I already told S it was fine, and now she's acting like nothing significant happened. She's suggesting we hang out, do crafts, and give me my birthday gift. Honestly, I don't want to see her right now. I don't know if I should bring up how I really feel, even though I initially said it was okay, or if I should just let it go. My mom's comment has also made me reconsider some things about our 7-year friendship. I've noticed that she does seem more supportive when I'm going through a tough time than when things are going well for me. So, Reddit, what should I do? AITA for still being upset? How do I even begin to address this with S when I already told her it was okay? Any advice on navigating this situation would be appreciated.