I have a beagle puppy who is four months old. He is normally a happy, active puppy who goes around licking everyone and loves to eat. Well three days ago that started to change. He started the day okay. Then as the day when on he go to where he was the same but he didn't eat any of his dinner. The next day he old ate what I hand feed him and he would run to everyone but no licking was involved. Today he is moving really slow and avoid everyone. What do you think is wrong with him?

Is he vaccinated?

If he hasn't been vaccinated yet being as young as he is and some of the symptoms your describing, it could possibly be Parvo (worse case scenario). Also being a puppy, you may want to take a look around at anything he may have gotten into that may have made him sick. Either way I would take him to the vet and have him checked out asap.

There are all sorts of things it could be, shots or no shots. The weekend and Christmas is over. You should be able to get into the vet tomorrow. Three days is plenty of time to see he isn't getting better on his own.