Best friend or bully?!?😔

Jess

So when I was in year 7 I meet this girl (f14). We became friend then this year in year 8, she has been really weird. Like she would always talk to her boyfriend and always leave me out. She would always talk about her self, I know he has family problems but she would never listen to my family problems and if I did tell her she would start talking about her family problems. When I started becoming sexually active with my boyfriend (she is a Christian girl and always talked about never doing that stuff) and as soon as she found out I did that she started doing it with her boyfriend, she would always rub it in my face. Some days at school I would be really sad because of my family problems and she would stay away from me because I wasn’t talking to her. Whenever She’s sad at school everyone comes up to her and asks her if she’s okay and everyone helps her but when I’m sad at school no one helps me or asks me if I’m okay. She wouldn’t even sit with me at recess and lunch. So at school I had to act happy so she would talk to me and it’s weird because our friends wouldn’t talk to me unless she does it’s like she’s controlled our friends (our friends are mostly boys) and all the teachers think we’re best friends and want to do everything together when she really makes me sad. It’s hard because my boyfriend hates her and he’s in year 9 and I’m in year 8 so I can’t talk to him in class if she upsets me I just have to go along with it. I’ve been dating my boyfriend for 3 years and she’s had 5 boyfriends in one year. Her boyfriend is in our class and it’s annoying. She really makes me sad and I hate my life but all I want is her to be a real friend and when I would message her that I was upset about something she had done she would send a massive message about how she’s sorry and everything but then in person she would do the exact same thing again and then I would message her again and it wouldn’t stop and she wouldn’t even care or say sorry. And it’s getting so bad I hate my self, I feel worthless and I don’t feel happy and I think I’ve started to get depression because i don’t wanna leave my room, I don’t feel happy around my family like I normally am and I get really bad anxiety whenever I have to leave the house. And it’s really hard because it’s only me and my mum at home.

What should I do?!? Please help!