How long is he like this?
Do his eyes dart back and forth?
Is he eating?
I am sorry your boy is having trouble.
He may have a disc or vertebra injury that acts up periodically.
Dogs can have strokes too:
He may just have become deydrated or hypoglycemic.
Put a few drops of pancake syrup in his mouth to raise his blood sugar.
Add plain pedialyte to his water 50/50
Check all over him and in his mouth for any abnormalities.Does he have any painful areas? Perhaps he injured a disc or verebra.
He should be seen by his vet ASAP for evaluation and medication.
Please let me know how he is doing. I will be here late.
I hope he feels better very soon.
Sincerest best wishes,