I need advice...

I have this friend and we have been best friends for the last 3 years but lately things have been changing. She has been more immersed in drama and is making friends with other very dramatic people. She has also started to treat me differently and has seemed to get really annoyed with me a lot. Rolling her eyes and glaring or making really passive aggressive comments.

There’s this guy that she used to like a few years ago but that has been over with for about a year and a half. This year, this guy and I have started to like each other and she has only been getting worse. She rolls her eyes when we are talking and texts me that I’m “stealing him” or that she wants me to “knock off the flirting” and stop walking between classes with him and stuff. She has mocked me and said really hurtful things but then apologizes later just to go back the next day. I always try to stay kind and honest but then if I tell anybody she says I’m breaking her trust. I don’t know what to do. We have been friends for so long and sometimes, when it’s just the two of us, things feel the way they used to but I don’t know if I can deal with the other side of things too.