What is her PROBLEM?

well i just read something about this kind of situation she is acting like she is your best friend and supports you but behind your back she tells all of the boys that you ever liked that you are a slut and she throws herself on them and gives them her number and when they reject you she tells them to lose her number and leave her alone so i think you should tell her to back off the guy that you like and she should find her own boyfriend so ya