How to get over your bestfriend?

I'm going to say, something that I might have never expressed and maybe I never will but I just want someone to tell me what to do about this, so lets say this person is A and A is someone I know of, but never anyone to call my friend but then after one trip we become good friends and then bestfriends and I happen to get addicted of A, we used to talk a lot like a lot, and then we get to know a lot of things about each other, I grew closer to A, I really don't know how A felt genuinely, so after some time I confessed but A was not ready for anything, and i can't even fully hate A because A never promised me anything we are just friends, but I think I just gave it a lot of meaning, A was alwasys kind to me and respects everyone too, but the thing is now when I think of A it disgusts me that how A is avaliable for everyone, but I don't know if its A's kindness but wasn't A is kind to me as well?