wow exgirlfriend

so i broke up with my girlfriend a month ago and shes been talking so much shit about me this entire month and im getting so pissed off. i know that she still likes me cuz my friends told me that she told them she does. and shes acting like a total bitch. so me and my friends were all talking and she friends with some of my friends and she came over said hi to everyone and i said hi to her you know to like acknowlegde her presence and the day before i went to the mall and bough a knew hoodie some shirts and got a hair cut and she doesnt say hi but tells me my hoody is to big and looks dumb and that my hair is to short and it looks bad held my tongue. should i like bitch her out and get in her face or should i just keep my mouth shut what do you guys think im so fucking pissed and im getting sick of her treating me like shit