Do Dogs Have Their "Blah" Days Like We Do?

I wondered this for the past several days as my sweet little Prissy dog was acting quite down. She was wanting to be "babied". She normally jumps up on the chair with me, but all of a sudden, she wasn't willing to jump up anymore. What happened to her? I looked all over to see if she hurt herself, but nothing was wrong. She was just acting like she was sad and wanted to sit with me. I let this continue, wondering what on earth was going on with her.....but after a couple of days of being babied, she finally went back to normal again and is back to her old barking, and jumping up and down self. I wonder, if dogs do go through a "blah" day or two, what makes them do this, and what happens to get them back on the normal track again? Anyone else experience this?