Is there any chance he got into something while you were gone?Could he have injured himself while you were out?What is your zip code?When was the last time he ate something?
Thanks for answering my questions.
I agree that there is something seriously wrong with your little guy. It almost sounds like either ingestion of a toxin or a head injury..however, it could also be something like a seizure since he's non-responsive really.
I did some checking and found an emergency clinic in your area here:
If this were my dog, I'd have him evaluated tonight, just to be on the safe side.
Please let me know how it goes!