Do I still stay with my friends?

When i got covid, I was off from school for a week maybe more. My bestfriend (Who I met in geography) and my other bestfriend (Who I had known most of my life) had seemed to of gotten closer, which i was very happy about at first, for the one i met in geography (We'll call her Amy) only thought of my other bestfriend (We'll call Sammy) as just a friend she didn't really talk much to, so i was so happy they were now close. But after a while i noticed that they were getting even closer and leaving me behind, but i ignored it for a while longer until my other friend started to ditch me to so i decided to make some plans with them, and it was really fun, until i whent to a party with them and i had this joke with sammy that we were 'wifes' until she started to say really mean stuff to me behind my back like "She is so annoying." and other stuff like that but again i thought it was just a joke until amy started to hit me and so i hit her back in self defence but sammy said that "You shouldnt hurt her she has done nothing to hurt you" when i have marks from her, in school things got worse amy who i always used to go with in any lessons always said no to pantering up and said she'll do the work on her own but then the next second i see her with sammy. Maybe im just overthinking but ive had panic attacks and self harm relapses because of this please tell me if im wrong for thinking they are leaving me.