Is something wrong with my dog? \:?

I'm not sure if hes just tired or I should take him to the vet or something.This morning when I woke up i opened his crate for him to come out but he just laid in there for 3 hours before I picked him up and carried him out and when I put him on the floor he just laid there... Usually he runs out of his crate all happy... Also, when I gave him water he just looked at it and didnt even try to drink it. Usually he drinks all of the water given to him... And also he doesn't walk. When i tried to take him to the bathroom outside he just waited for me to carry him and i had to put him on the grass. And when I brought him inside he just stood on the floor then I carried him onto the couch and he just slept more. What should I do & can you guys please tell me whats wrong with him? Maybe hes just tired... Im not sure but Im worried ):