Rejection, Crushes, Feelings, Frustration. *Venting*

(Thank you in advance for reading this huge vent)
Yesterday I was rejected, so to speak, by someone whom I was/am crushing really hard on. They weren't mean about it, in fact they were extremely kind, but that feeling of rejectment still hurts. I was having a bad day as it was, and I almost had a panic attack when I got to the High School after Band practice because they switched practice locations without alerting me about it beforehand, and I had no idea where anyone was. No one was in the Auditorium, and I looked all around the hallways. My phone was dead so I couldn't call anyone, and all I had was my chromebook, but sending an email would do no good. Finally I walked back to the Auditorium doors and heard everyone in the Chorus room. I was on the verge of sobbing and I looked like a total wreck, and felt like one, too! That plus the rejectment hit hard, but I played it off as I usually do at school. I know that I'll get over it but it's difficult. They were my first huge crush. Sigh.
So, I have another crush. They like me back, but they have a boyfriend. They say that their boyfriend doesn't mind if they have a girlfriend while they are dating, but I'm not comfortable being in a relationship with someone who is already dating someone (who has said that they will propose to her when she turns 21). It's difficult. It's confusing. I really like her, but she's taken and I can't deal with that emotional stress.
One of my close friends is drifting away from me. I try my best to improve in social situations, but it's not my strength. I think that he often takes me for granted. I also feel that he doesn't care about how I feel half of the time. He's never a good friend when other people are around. I don't know if it's because he's closeted or if it's just because I'm not all that important to him. I want to tell him how I feel but it's difficult because my emotions get the better of me. We get into fights alot because of how he always has to be Mr. I-Know-Everything. I mean, I get it, he's smart, but that's not really an excuse to be a straight up jerk to people as if he's better than us. He disagrees with everything I say even when I'm saying the exact same thing he is. He makes me feel worthless sometimes.
There is a girl in my class, all of them (even special AND gym), who is pushing all of my buttons and crossing everyone's lines. I can't stand her. She thinks that the world revolves around her and that she's all that, but she isn't. It's always the same thing, every single day. She interrupts class, calls out, yells at everyone, disagrees with everything anyone says ever, has this attitude in her voice, makes dumb jokes that no one thinks are funny, makes fun of people, makes up stupid nicknames that nobody enjoys, keeps doing things even after she's told to stop doing them, talks about teachers behind their backs, destroys teacher's personal property, laughs like a psycho maniac (literally) and scares everyone on purpose, then laughs at them and mimics their reactions, and is an all-around b:***:. I can't take it anymore. I really want to change sections, but I can't. Ugh. :bang:

This is just a crazy vent. I'm going through a lot and I have to get it all out. :icon_sad:

 

Update:
Had another mental breakdown at play practice after a huge fight with my "close friend" that I've been having issues with. He said he was sincerely sorry and that he didn't know he was hurting me, but his actions speak louder than his words and his actions haven't confirmed that he actually gives a :***: about me. It's getting stressful.