This girl is still very young and clearly immature which tends to present what you may consider narcissistic issues. It sounds like she may also be struggling with borderline personality disorder. It sounds like she doesn't know "what" she wants and is afraid of being hurt and tends to end up in situations where she has been a victim too.

It sounds like this relationship is hurting and confusing you and you are growing tired of not knowing what to expect next from her. You sound like a caring person, but you do have to make sure you don't end up having this relationship turn you into a codependent that allows her to hurt you over and over again. It really sounds like she needs professional help and you are not a professional therapist.

It sounds like you may need to just disconnect from her instead of constantly being hurt and that can be hard to do when you are a nice person and "care" about her well being.

Whatever you do in this, try not to hurt her, just let her go understanding that in doing so it allows you to continue to grow as a person yourself and find someone that can appreciate how kind hearted you are.