I feel like she's not real and has a grudge with me - should I drop her?

Any kind of relationship, whether it's a friendship, with a significant other, or with family, should be "give-give." From your description, you don't trust her to give you her "real" side all of the time. You stated that she only speaks to you when she needs something and does not return friendly texts and did not stand up for you or console you when your feelings were hurt, thus implying that she would not be there if you really needed her support. Who needs a friend that is a user? People change as they grow and meet different experiences. Despite your history with her, it is apparent that she's not showing the kind of caring needed to sustain a friendship. Friendships are needed to maintain a healthy emotional life with support and comradery. When a friendship brings more grief and unease into your life than the other, then it's time to end it.