It was good that you helped this girl. I am a bit concerned though with "we fell in love" when it comes to you. This girl was being abused, was very needy is that the kind of partner you want? It sounds like your relationship consisted of you constantly helping "her", she was not really providing you with a "healthy" relationship. Truth is considering what you have shared here of her dysfunctional family life, she probably doesn't even know "how" to have a healthy relationship. Watch out for these red flags because it won't be healthy for you to end up being the "caregiver" in your relationship, after all you have needs yourself, and her suddenly dropping you is proof that she is not really thinking of you the way a person in a healthier relationship would.

Other posters are right in that "learn" from this relationship and be honest about what it really consisted of for you. You sound young yet, keep studying psychology, there is much to learn and don't be so quick to give your heart away, LEARN first.