I had the same problem with my grey tabby Tommy Girl. She was a real sweety pie and either sat on my lap or the right side corner. I got her fixed and for a couple of months she was a real pain. Nothing in the house was safe from her -she terrorized my dog and cat and then all of a sudden she was back to her old sweet self. Then she moved out and for the last 5 1/2 years she refuses to come in the house. No matter what the weather. She now has her own little house on the back porch,only uses it if the wind is cold other wise she prefers to lay in the rain and snow. Go figure