This is abandonment, pure and simple.

Was she your college counselor? I don't understand why she switched the roles and became your tutor. Is this allowed by your college policies? I see you are in England, so may be ethical rules are different there. I don't know of any college here, in the US that would allow those who work in counseling department switch their role with students. I can't imagine this would be possible here. That's why I am very uncomfortable with the idea of her switching the roles in the first place. Even if it's not technically unethical, it's very mindless on her part to do so. To have a tutor who also knows some very intimate, personal details of your life is not something I'd consider healthy. She should've thought about "conflict of interests" or all kinds of implications this switch could create before, not after she did that. Now, after she confused you about her role, she is cutting cord because she is feeling uncomfortable about the situation. This is cruel and unfair to you. On the other hand, I am not sure that continuing to see her as a counselor is the best solution. I think, the best and the cleanest way to resolve this is for her to take responsibility for her mistake, to apologize to you for whatever pain her mistake caused you and to help you find appropriate help.