is it possible?

My dog who is usually bouncing off the walls, actually looks sick. Is that possible? His face actually looks different than it usually does. He hasn't eaten all day. His "daddy" babies him constantly. Can he miss him so much
that he will seem or get :( sick?

It's entirely possible for an animal to "miss" a human companion when they are away. Some times it's so bad they get separation anxiety. If he continues to refuse to eat I would try mixing some warm water in with his food to entice him to eat.

How is his nose? Is it cool and damp, as normal?

And yes, our first St. Bernard, Freckles, would pout, mope and look depressed when my mom left for a week for a convention each year. She wouldn't eat much at all the first night - and this was 185 pounds of dog - and would only grudgingly accept food the second night, and would refuse it entirely if my Dad touched it (he drove Ma to the bus - a.k.a. "took mommy away") but would eat if us kids stirred her food.