Good friends are hard to find

[Mandy]

She sounds like an insecure person, and hopefully for her, she will change and come to realise that it in reality it works differently. I'm sure her therapist has picked this up, and will work her through this.

Don't give up on her, there is going to come a time that she is going to need you, and she will open up. Give her time.
Distance yourself a little if that's what you want, but let her know that you are there for her.

Good luck.