Your perfectly housetrained angel is having accidents in the house. Or once gentle and tolerant, he’s now growling at the kids. A change in behavior can indicate that something isn’t right. Growling or shaking can indicate pain.
And potty accidents could be a urinary tract infection or even a kidney issue. If your dog has always been well-behaved and something is off, don’t assume he’s being bad — he may be trying to tell you something in a way you’ll understand.