Weenie mystery

Last night Heidi and I went out to Walmart and HEB for a few minutes. It was cool enough for her to stay in the car. She stayed in the floorboard as usual. Makes me wonder why she wants to go.
When we returned home, she ran around growling and barking in an unusual way and it made me feel as if she sensed something wrong in our house. She never focused on an area, so I eventually felt she was just bitching. We had workmen in the house during the day and perhaps it upset her to come back in the house and pick up their scent or something.
Today, when I returned home from the nursing home, she didn't greet me at the door. Her little black nose is almost always is in the crack of the door as soon as I began to open it. I walked in, no Heidi to greet me. I called her name - nothing. I glanced behind my recliner where I saw a darker form than the rest of the room. I spoke directly to the form and out bounded Heidi, tail wagging. I went back outside for a minute and when I came back in, she was again hiding behind the recliner. The recliner is her safe spot. I can't figure out what happened to her to make her hide like that.