My dog is usually hyper and crazy. Lately, he has been mopey. His nose is dry and his ears are cold for it being summer. I just gave him a lot of attention, but he still seems mopey. Could he be sick? What could be wrong with him?

Is this the same dog?
https://www.askmehelpdesk.com/dogs/why-does-dog-poop-house-night-same-spot-473965.html

Has he been to the vet for a check up recently?

Does he perk up any at night when the heat of the day wears off?

Any changes in his eating and drinking? What about bowel movements and urinating?

I think it's time for a check up at the vet.