Hi again, and thanks for your very helpful reply.
It's possible that Petsmart sold you a sick hamster. From your description of his symptoms, he may have an infection in his system or, if he feels sort of cold it might be because he got out earlier today and was running around. Try to keep him warm by keeping the room he's in, warmish and make sure he has a little 'house' to go into to sleep. Hamsters are nocturnal and are usually more active at night and less active during the day, so his entire schedule may be off.
I'm sorry, but I can't do a phone call right now, as it's almost time for me to sign offline for the night.
If you have an ER vet center nearby, call and ask if they treat hamsters and if so, I'd bring him in, asap. If he hasn't eaten or drunk anything, his eyes are closed and he's breathing lightly, plus, he's cold, there's a possibility that he is entering hibernation mode and that is not safe for him. Here is more information: CLICK
Wrap him in a warm cloth or towel and gently rub his body until you can get him to a vet, right away. He may be dehydrated and the vet will need to administer fluids I.V. or under the skin.
I hope all will be well with your hammy! Please let me know how he's doing. Thanks!