Please don't get angry with him. He is obviously confused, or as Carrie says, has a medical problem. While you are getting through this, make it easier on yourself, put him in a smaller area so that it is easier to clean up after him while this is going on. I'd use gates versus closed doors. That way he can still interact with sounds and sights in the rest of the house.

And after ruling out a medical problem, do as was suggested, start over with him. In addition to retraining, he will be getting the attention from you that he probably needs right now, on a consistent basis.

One more thing. Are you taking up his water at night? I would do that. Pick a time, maybe 7-8 pm and take the water up until the following morning. He's old enough to go without the water during the night. Make sure you take him out and he "goes" right before bedtime, and then again, first thing in the morning.

These things take time to correct, but they can be corrected with lots of love and positive reinforcement.

Good luck.
Logan