I am so, so sorry.
But you did something wonderful for Nelly. You took her away from that hell hole she was imprisoned in and brought her love and taught her to trust. What's more, you succeeded when someone else had failed, taking on the toughest job of all and succeeding. Because of you, Nelly had the kind of happiness that she probably didn't even dream existed when she was living in the dark. I know how terrible you must feel now but think of all the joy you brought her. Losing her is terrible but how much worse it would have been if she hadn't known you at all.
Thinking of you and trying not to cry even more.
Annie x