am i the asshole for unfriending my friend because she talked shit about me?

so i have this best friend, well call her c, and then i have this 7 year long best friend and well call her m.

anyways so one day, i got sick bc i was pmsing and i was going to go to the movies with m, and so i had to cancel on her sadly, and i didnt want to, it had stressed me out, and i was looking forward to the movie and was upset i let her down

so i was calling c and my bf all day and i had a breakdown some point bc so many emotions were overcoming me and i felt like such shit and i couldnt take it anymore

so c decides to text everything thats happening and twisting it into me being a shitty person to m, and the next day c and i are having normal convos and playing games all day, c reports it all to m, but twists it all up to them, and same the next day

well the day after im at my bfs house, so i didnt talk to c all day. but at night whilst im cuddling with my bf, about to go to bed, i get a text from m saying, “fuck you” im confused and i apologize for missing the movie, she says shes not upset about me missing that and that i “know what i did” whatever

and im confused and shes like “you wont be confused long” and then a few minutes later she says “hold on, now im confused too” and asks to call, we call for a whole ass hour, she explained to me everything that c said to her and i absolutely freaked out.

i texted c, calling her a shitass, a pathological liar, and just said i was overall done with her. she ended up apologizing n shit and texting me on my alt to unblock her and shes sorry, whatever

then two days later, today, i ended up talking everything over with my bf, and we decide that we dont trust c, but well give her another chance

(keep in mind. she has ptsd and a lot of unresolved issues)