So many theories! Skin walker, familiar, reincarnated human, inhuman spirit/demon, or perhaps paranoia? I read that if your dog suddenly starts acting human they are mimicking or in-tune with your emotions and facial expressions. There’s also a certain muscle that exposes the whites of the eyes giving the dog a more human appearance. I wonder if you found this dog by happenstance or adopted? Anyway good luck, I hope your situation gets better!