I have a twin sister, we're in high school, we used to always take classes together ever since kindergarten, now she suddenly doesn't want to anymore and she doesn't even want to hang out with me at school, she has a boyfriend now that she loves to be with, and whenever I try to talk to him too she gets mad and thinks I want her and I to "share" him. We would also dress very similar or the same and now she's started getting really mad whenever I put on a matching outfit. I feel like I'm being neglected by her all of a sudden when we used to be so close and spent almost every minute together. What should I do? How can I get her to stop acting like this and getting upset about everything?