Quote Originally Posted by Nobas Mom
Believe me rehoming him is NOT an option, I just had that passing thought due to sheer frustration and the thought that he is not happy anymore. I couldn't bear to part with him. I'm hoping the vet work-up will show nothing, and that it comes down to newly developed behavioral problems. I just started this second job about three weeks ago, he had his neuter surgery last week (and was cooped up all week recovering) and this week the weather has not been conducive to going outside much, so I'm hoping he's just acting out...
All of those things (new schedule, surgery, weather) can cause a reverse in potty training behavior. However, as he's drinking more, you will want to do the vet thing first.

And, yes, you will have to "regress" in training. This is common with dogs. My students are always amazed and frustrated when their dogs suddenly don't seem to know a behavior they had rock solid a day before. Suddenly, the dog won't sit, and looks at their owner like they've never even heard the word. A good trainer's response is to expect this and to take the dog back to square one and retrain. The good news is the retraining is usually much shorter than the original training.

Even dogs who have had a behavior for years can suddenly lose it. Don't worry. It's common. My MACH sheltie just lost his "straight" or "go" directional in agility. One day he'll "straight" a series of obstacles up to 60 feet away from me, and the next day, poof, it's gone. I just had to go retrain it. It's back now, as strong as ever. The trick as a competition trainer is to catch these behaviors falling apart before they cause you problems in the ring. For housedog owners, the trick is to catch them before they cause frustration and further problems.