advice? just a vent about my friend </3

So there is a friend of mine that, fortunately, doesn't have an account here, but I will still keep anonymous because, like, I'm not that much of a dushbag... but I still would like some advice.

Basically, it all started as a cool friendship. They never had friends, I never had friends, PERFECT MATCH!...right? Well, at first, yeah! We were buddies. I always made jokes to make them laugh, and normal stuff like that. I also went to her house multiple times and let her handle my videogames since they never had any... somehow– but then, I started to get a bit sick of them, as they started acting a little... strange, I started noticing how they kept forgetting school stuff, 'can happen' I thought. Then it became asking me for every single homework, 'a little stretch tbh, but that's fine!' It's not like I never did it, then it became to comfort to her when they get an average grade. Sure, strict parents exist but... I realised they hadn't done any of it back. At times, she would get angry at me for asking! So I secretly asked the teacher to separate us, and so the teacher did. It was amazing to have some alone time, but then I found out she was able to form a 5/more person friend group, and they are now inseparable. I'll let you know, even if I wanted some space, literally, I NEVER ended our friendship. I always answered them if they asked for something, kept handing out stuff, and they became more and more rude! They never again sat next to me and almost only talk with them! I started to get a little irritated. Can they have more friends? OF COURSE! I ALSO HAVE OTHER FRIENDS OUTSIDE OF SCHOOL! But, just clearly trying to cut me out like that?

Then today arrived. Recently we had to go from class to class because the window in our main classroom fell on one of my only friends! Long, long story, but she wasn't in school for good reasons, meaning I was basically alone again, and then something just happened. The teachers got mixed up in the classrooms and there was incredible confusion about where to go for the other 2 school hours. I told them, "I think we are in room 211" and when I found out that wasn't the case, I asked the teacher to go find them and tell them, but the teacher didn't let me. When they got back, they hit me in the head with the backpack and when I called them out for that they sed:" You deserve it", like, dude?! I, of course, snapped, but not too much. Fortunately, I'm pretty contained. I just told them that I tried my best to tell them and that they could go fudghe them self (a little more offensive tho), and they went to sit with their new big friend group, and only try to appologise during the break, but, for all I did for them and how they treated me recently, I kinda feel...yk like they aren't as truthfull as they claim too, IDK let me know what you think ig