What should i do about my friend?

Kay so my best friend before used to always tease me in a friendly way and like hit me in a kind "sup budddiee" kine way. But now. she always calls me stupid. Constanly im really tired of it. and SHES NOT JOKING. every time i go next to her she says "gtfa Stupid ***" and im just like omg. And she only comes to me when she wants somthine and she always hits me for no reason. For her fun. i can already say i almost got injured. Since after my cross country practice she kicked me in the back of my legs causing me to fall even when my legs were worn out from practice. should i tell someone? should i just let her, or should i just find a new so called "Best Friend"?