How do i stop my best friend hating me?

okay so i have this friend and we have been really close since we were really little and the other day we did this harry potter sorting hat thing on this website anyway she got put in gryffindor and i got put in slytherin and when i showed her she said that all the dark and most evil wizards have come from slytherin and then she punched me in the face and i asked her why and she said that i might be playing a trick on her because im evil and she panicked and smacked me in the head. i forgave her for it and we carried on being friends and i came over to her house and she whips out this stick and yells avada cadavra. i just walked out without saying anything. now she doesnt return my calls and i called her yesterday to ask if she wanted to come to the park and she said no tom and i said what whos tom and she said it might be another slytherin trick and hung up. i dont know what to do about her anymore please help