My cat had fleas and he was constantly licking, fur was coming off and he lost weight. Vet gave him a shot and a pill, he started to gain weight again and returned to his old self and bothering the dog and playing. He stopped for a while but actually did have to have the shot and pill twice. Where he licked the fur off in the beginning all grew back. He is still his playful self but he is licking again and his hind legs are losing fur and one side of his backend by his tail. He is eating, but he first time this happened he wasn't eating. He is constantly licking. About 3 months ago we did have to have our dog put to sleep, but don't know if this is the reason now or not. We just got another dog two days ago and the cat and he aren't jumping to se each other, but they aren't running away from each other either. I'm not sure what is wrong.