He may have gotten into something he shouldn't have or he may have hit his head. That would make him very disoriented. In any case- I would play it on the safe side and see a vet as soon as you can. Good Luck!
My Dog Seems Disoriented And Can't Relax. Every Time He Lays Down He Gets Up Quickly And Begins To Pace. While Pacing He Stops, Takes A Step Back And Moves To The Side Like He's Trying To Walk Around Something, But Nothing Is There. How Can I Help?
Your dog is probably having (or had) a seizure- You can help him or her by making sure it doesn't run into things and don't stick your hand into its mouth, it might bite you