May have gotten into something poisonous, get him to the vet for proper diagnosis and treatment. Best wishes.
Definitely sounds like he has eaten something toxic. A lot of plants will cause these reactions if ingested. Call your vet asap, and good luck!
It could be that your pup is in pain, they can't tell you when they hurt, and don't know how to. I think you might need to take the pup to the vet to make sure that something isn't going to make the pup even sicker. Hope this helps, good luck to you and the pup.
If you just got it its not use to the house
You better get him to the vet fast, it kind of sounds like rabies! Do you know if he was bitten by something? Hope this helps, good luck to you.