Becoming and staying friends with somebody with whom you have mutual attraction (especially if the attraction is both physical and emotional) is a big challenge. It's asking a lot of yourself and of her to be able to manage that at your age / stage of life, especially since neither of you are in a committed relationship with anybody else.
In my personal experience, probably the most difficult thing about being in my late teens / early 20s was being able to say specifically, honestly, and truthfully what I wanted. Knowing what you really want requires you to be in touch with your feelings and able to articulate them to yourself and probably to others. That's really not very simple, or easy.
It sounds to me like your friend doesn't know what she wants, and it sounds like you're not entirely sure, either, which is why you're on here asking for advice.
I'm a big believer that in this life we are not blessed with very many opportunities to meet people with whom we share a deep, meaningful connection. It sounds like there is at least the potential of that for you with this person. I agree with others that the simplest and most effective solution may be to put distance between you and her, at least for a while. However, I'd caution you not to completely cut ties, if it's possible, if you feel like this is that rare sort of person. You could truly regret it later.
First and foremost is to do what you need to do for yourself to be happy. You won't be able to approach situations like this, or personal relationships in general, with a clear and level mind until you are secure and happy with yourself. It sounds like putting some distance between you and her, at least temporarily, is necessary for that to happen.