We will know more soon....

For any of you who know the cat in the picture, you know that it is beyond strange for him to stop eating. Well, that happened about 4 days ago. I changed his food, and the same thing-- no eating. He won't even eat the smelliest of all smelly pouches of nastiness. He is refusing cat milk-- his favorite.
We are going to the doctor today. Hopefully, his daily medication for thyroid just needs adjustment.
But, he is 14 years old, and so I'm a little more than worried.