Love, obsession or something else? [Very long]?

First, I very much respect you for putting your heart into healing this girls. It must have been nice for her to have a new person accept them and help then through so much hard subjects. So, I commend you for that. I think you should look up the term 'limerence', because it sounds a lot like what you are going through. You were very smart in the situation and I think you handled it as well as possible, to stop communications with her. Be confident that she will be fine, because truly there is no way you could have hurt her by all the good that you did. In fact, she probably felt good to know somebody felt feelings for her, which will give her confidence in future relationships. Good luck to you (: