I'm just going to throw a few things out there that may or may not fit...

Do you have anxiety struggles in your life or is this sort of dynamic limited to your interaction with this one friend? I'm asking about anxiety as I suffer from anxiety and I know that I tend to over-analyze relationships and whether or not people really like me.

Do you think it would help you if you were to branch out and make new friends with other people? Maybe it would show (prove) to yourself that people do like you for you, and its not just this one person who doesn't like you but hangs out with you anyway (for whatever reason). I'm not saying that is what your friend is doing, but it sounds like you think she doesn't like you for you. (I hope this makes sense, sorry, I'm quite tired.)

Maybe I don't clearly understand the situation, and for that I am sorry----just trying to throw a few ideas out there.