Vet, vet, vet....to first rule out a medical condition. Nuetering, nuetering, nuetering, cause the world doesn't need more pets. Nuetering CAN help with the territorial...but, two things. First, it doesn't always, and second, it takes some time even after the Sir Jury...

I think after the trip to the vets, I would return to puppy potty training....crate, confinement, positive rewards for "potty", frequent trips outside, etc. Something is upsetting the doggie. You have to figure it out, as he can't tell you. Maybe closing off ALL rooms that you can might help, too. I bet if it isn't a medical problem, there is something new around the house/life, that you are overlooking....