Do you think this is something to be worried about with my dog?

I left home yesterday and came home late, but my dog was still with 2 people in the house. They said while i was gone they found her in the laundry room, just shaking. I asked if there were thunders because dogs are scared of them, but they said there werent. Im thinking what couldve caused it. Do you think its something bad?
Do you think this is something to be worried about with my dog?
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