I am sure that she is now at Rainbow Bridge enjoying warm sunshine and cool breeze and green meadow. I believe that she now no longer feels any pains or sorrows, yet deep in her heart she is waiting for the day of reunion.
Yes, pain will leave and happy memories return. Yes, I know that it would be selfish and cruel to keep her around knowing that she was getting weaker and weaker, but it hurts so much to have to let her go!!