Hey,

I think your better of without her simply because she seems to be putting you into a state where you have to question things. These normally end in a bad way and will affect you a lot more mentality. I'm going to talk about myself...

When people did this to me, it would trigger a depression state for me which would last days. I realized that I'm better of without the other because it wasn't any good for my bipolar and I have a lot to deal with. Bipolar is tough and you need support not people who you have to second guess.

I'm sure it will be tough in the beginning short-term, but long-term I think it will do you better. Also,

I've learned when you do things for others WITHOUT expecting anything in return you'll be much happier. You got her a gift but you should only do it and NOT expect anything in return. This way you are NOT left upset or second guessing again.

Hope this helped a little, but hang in their and cut it now before it's too late. Friends like this are a dime a dozen, but true friends come rarely. I'm sure you'll find someone way better.