Can you call the place and ask how he's doing? You might be surprised, he may be having a great time. When you go to pick him up, just act like it's the most normal thing in the world, be happy to see him, give him lovin, but don't behave like you just realized you left him with an axe murderer all day.
Be calm, positive and upbeat, don't coddle him if he's acting all freaked out. Talk to him in a firm calm voice and when he settles down give him a treat.
Unless he has a total meltdown tonight, I wouldn't judge if this was a bad thing and give it a few more times to see if he won't figure out how much fun it is.
Please let us know how he's doing, once you get home.
