My friend is being really mean to me?

My friend and I have lots of fun when its just us. When ever another one of her friends come along, she puts me down, makes fun of me, and says some really rude things to me because its obvious shes trying to impress her friend. Today she told me to come to the park with her and her friend, and to bring my friend and our other friend. So I got ready quickly and ran to the park, but as soon as we got there, she started bragging about her, "Computer Hacking Skills." I laughed and playfully said back, "You can't hack anything for your life! lol!" She then grunted and told her friend, "This is what I have to deal with." Later on her and her friend went on and on about how she knows things I don't know about me. I was getting fed up by then. I told them, "Sure, you don't know anything about me." Suddenly my friend bursts out saying, "YES I DO IDIOT! I CAN RUIN YOUR LIFE!" Now shes texting me and calling me a liar! What do I do!! I'm sick of her! I hate her! Shes a horrible friend that I can't trust! She sent a boy I liked pictures of me she took on webcam of me making dumb faces. Later on she tells someone online my secrets that I only told her! She tried to trick me by making me say dumb and gross things, then copying and pasting them to the person online, saying that those are things I have done before! What should I do to make her stop already ruining my life!