Stupid

I feel so fucking stupid. I had so many people tell me that my friend was using me and that she was only going to fuck me over in the end, and did I listen... No of course not. So here I am feeling like a total fool, and feeling betrayed as to why she would go and talk shit about me to my other friend. This is the end of it. I've dealt with her backstabbing ways for to long and now I just don't know how to tell her this...
I realize I have like no friends at all but this is too much for me. I'd rather have non at all than get hurt every other week. I've said so many times that I wasn't going to talk to her but I just don't know how to do it. We've been friends since second grade and now we're in eleventh I just don't know what to do anymore...So if anyone reads this, can you please give me some advice as of what to do?
I will deeply appreciate it.