So, for context I(M16) am very much considering breaking up with my girlfriend(F15). We're both in highschool band, and so are most of our friends. I know it's highschool and this happens all the time, but all of my friends are her friends, and I don't want them disliking me because I was the one being stupid. Anyways, we've been together for about like 2 years believe it or not, and we've been going strong till recently. We've been so close that I'm scared of what will happen once we break up.

Sorry if things are still unclear, but anyways onto the actual stuff. So, recently we haven't really been talking, and I haven't been going over to her house as much. At first I thought it was fine, but at this point it's clear that this isn't a relationship. It's also seemed to me that she cares more about her friends than me. Among other things, she'll say goodbye to her freinds in the hall with an arm touch and saying I love you or something, and all I get is a bye. Except she doesn't even bother to look at me, she just walks away and says bye without even facing me. That's when it first started, and things have just been going downhill, like there's this girl, I guess I'll go by a codename so ava, anyways ava is a good friend of mine and a good friend of my gf, and she's gay. Oh, also my gf is bisexual, this will come into play later. Anyways, we're all good friends, and that's why I maybe haven't seen any of these things till now. Things like how she touches up on all her girl friends, and how she speaks to all her girl friends rather than her guy friends, including me. Anyways, she's always made fun of me, including her friends, it's typically harmless stuff like how I'm a tryhard or a sweat or a nerd because I enjoy band, but I typically just pass it off as harmless jokes and ignore it. But last Tuesday, April fools to be exact, things were different. She started making fun of me for grabbing a saxophone which is not my main instrument, so she was calling me a need and whatnot. I didn't mind, but then I saw that when ava grabbed a saxophone too to play with me, which isn't her normal instrument either, nothing was said. Then, we were playing some small ensemble music, and thus we were both playing the same lines. When I played it in the beggining, I was just joked about, but I kid you not, when ava started playing the same exact thing later my girlfriend was appraising her for being so good to play multiple instruments. This really ticked me off, but I decided to ignore it as she probably didn't mean anything by it. And then I noticed that my girlfriend had grabbed a chair and sat with us, but instead of sitting between us, she decided to sit on the other side of ava, so not next to me at all. I kept playing though, and eventually saw my gf touching avas leg, and once she saw me looking, she tried to play it off as she was touching the saxophone buttons. I had more than enough time to see her doing it though. Then, later with all her friends standing around ava and me playing, she was doing these like April fools jokes, just saying random things then saying April fools. She kept saying she's gay not april fools, which I though was weird but she was kinda gay I guess so I didn't really care. Then, I kid you not again, she said I Love Ava, Not April Fools... yes she said just that, that wasn't a typo. This brings me to my main point, is this a good reason to consider breaking up? I'm pretty sure that's not cool. And after she said that, I stared at her for a good five seconds, then got up and left. She saw me leave, and I know she could see me as I could see her on the other side of the band room. But she never came over to check up on me or explain herself or anything. Then, later I talked to her about it and how I didn't like it, but all I said was I didn't like what you did, and she knew exactly what I was talking about. I said nothing about what she did exactly, but this tells me that she clearly knew what she did, and knew that it affected me and it was cool, but she never talked about it till I said something. This isn't even close to everything I have to complain about, but that was my main question.

Sorry if this whole thing is super unorganized or just bad in general, I'm tired and have for some reason am struggling to think straight.