AITAH for being upset at someone because they started dating the guy I like, even though he rejected me?

So basically, i’m (16 F) in this music program and there was this guy I liked for 2 years (17M) but couldn’t bring up the courage to make a move. But then, one day I asked him to go to a festival with just the two of us. It went well for the most part, and we both had fun. We would also call sometimes. When he couldn’t, he would always explain in detail why. I thought he liked me at one point. But then he became distant. I asked the guy if we ever had anything going on between us, and he said no, and that he had no idea that I liked him.

In October, my former good friend, (18 F)told me that she started to like him. I was glad she was honest with me, but I asked her if she would pursue him. She said yes, knowing that I had liked him for so long. We called for a bit, which didn’t go well because she wouldn’t listen to me and just say things like, “sorry i’m a bad friend.” He had just rejected me a couple days ago, so that was her excuse to why she could date him. She is also a senior in HS, and he is a junior. So I felt like them dating would be pointless. keep in mind I was calm throughout this whole situation to her and never name called or yelled.

Then, I decided to send her a paragraph because I was feeling so many emotions during the call and I couldn’t express myself. The paragraph says,

“i’m truly disheartened that you would rather have me dislike you and lose our friendship to be with a guy, than stay friends with me. it’s telling me that men are more important to you than your friendships. i know i can’t stop you from doing what you want to do, but im just trying to say this would really hurt me and put a barrier between us. i think it’s disrespectful that you are only thinking about yourself in this situation, and not considering my feelings. men are not the center of happiness. i really felt like you were guilt tripping me on facetime, because you were saying stuff like “im sorry im a bad friend.” that really made me feel like you were invalidating my feelings and trying to guilt trip me. i thought that this stuff was girl code since elementary school, meaning that you can’t go for someone that your friend likes. i remember you said something along the lines of that when you like someone another person has a problem with it. have you ever considered their feelings as well? you also said how i kind of “manipulated” you because of what I said to you a couple weeks ago. i was not trying to manipulate you at all, instead i was speaking my feelings and trying to help you understand me. I’ve moved passed the idea of me and him, but i haven’t moved passed the idea of you trying to be with him. I’m way more upset about you trying to go for him. i know i can’t change your mind and i know you may just think i’m in the wrong, but i just want you to know that trying to pursue a relationship with him will hurt me and our friendship deeply. our friendship is already damaged, but it’s fixable if you try to understand me and realize what you’re doing isn’t right. i obviously can’t stop you from doing what you want, but if you do end up asking him out i don’t think i could just ignore it and still be your friend. it’s you’re choice to make so choose it however you want to.” 

She never responded to that message. From mutual friends, people were saying that she thought that I basically called her a whore, which was not my intention, and she was MAD.

Few weeks pass by and they start dating. When I found out the news, my heart shattered. I made the awful decision to end my life, and obviously I survived, but I was in the mental hospital for a little bit. No one knew where I was and what happened except for my parents. We had a gig the day I was sent to the ER. My bandmates were furious.

After a week or two, my bandmates realize that no one has heard of me since that day. They start making assumptions. The girl that I have problems with, she started assuming that I was in the psych ward, and told people that. This girl is EIGHTEEN, and at the time I was fifteen. I also forgot to add that she has already done this to another girl in the program, which is insane.

I have to see them twice a week for 6 hours, and now i’m finally starting to get used to it. Please be honest about your opinions and answers, I greatly appreciate it. (Ik it’s not that serious of a problem but i’m still upset)