Major friendship Problem what do I do please help?

So here I am, Zoe with lots of friends, two of which don't get along well because they both want me. One is called Amy the other is jess. Amy has a huge, serious problem with me and jess being friends and she thinks she is my only best friend when actually I have lots of best friends including jess and she accuses me of spending time with jess too much and being close to her and she has done this at least 5 times to me before but she drove me right off today and I'm so upset I don't know what to do but please be realistic thanks xx