Is she elderly? There is a condition that occurs in some geriatric dogs called cognitive dysfunction syndrome (CDS) that can cause that type of behavior. It is a bit like alzheimers. I had a dog that had CDS for the last 3 years of his life. It started with him wandering aimlessly through the house and getting stuck behind furniture. He stared at walls and couldn't remember how to go up and down stairs. As time went on he no longer recognized me or anybody else in the family. He was afraid of us and if anybody touched him he would flinch and scuttle away. He spent most of his days pacing around in circles.
Most dogs with CDS will at some point lose their housebreaking skills and many bark or howl incessantly. (Mine didn't, fortunately.)
Sounds like a visit to the vet would be a good first step in pinning down what is going on. Best of luck to you and your dog. I hope it is something minor and she is back to her old self soon.