Please help! I do not know what to do!?

Friendships are like relationships, sometimes they just run their course and people drift apart or grow tired of each other and no matter how you try and patch things up, things usually can never be exactly the same as before the rift. I think this has happened to you two girls and I feel you should just make new friends and never mind anymore about Cathy, as much as that hurts, you cant make someone like you as much as you like them and you have no control over how someone else behaves or what they say. I do not feel Cathy is going to apologise to you and I think you should just distance yourself from her.