my best friend is really pissing me off

okay, so me and my best friend have been freinds for 10+ years. well ever since we started high school she's been this fake bitch ever since. she talks shit about a person one day and literally hangs out and calls them her best friend the next day. well I texted her about 3hrs ago to wish her a happy birthday and she still hasnt even opened it and she's been posting on sc with her "best friend" she was talking shit about the last time we hung out. she talked shit about me a lot this past year but it's okay she talks shit about me but the second that her name comes out of my mouth she wants to fight me. I just realized this past month thats she's a fake hoe and I dont need this kind of influence on my life, but she's been my friend for a really long time and I dont just wanna stop being friends with her cause we've been through so much. idk what to doooooo.