Thanks for your advice. I will take him to a vet because I love him so much, I don't know what I will do without him. In order to keep his weight steady, I have been feeding him three meals of soft food, as well as his regular hard food, per day. He also gets a small portion of my food. I hope it is nothing more than his thyroid acting up, like you said it might be. I will keep you updated. Thanks again.