What should I do? ?

I've been friends with her since a very young age I'm 22 and she's 2 year older. She always makes bitchy remarks and tries to embarrass me in front of guys. She sent a weird giff to me over messenger  trying to get a reaction out of me and I just put a laughing face. When I've got close to a guys she always spoils it by saying stuff about me to them. It seems like jealousy but I don't understand why she's got a boyfriend. It's like she doesn't want to see me doing well or going further with my life. My sister said I need to cut ties with her but she's the only friend I have really.