M.R.
I do that too and I know others who do it. I like to blame it on too many movies. If you are anxious all day, then that would be over-the-top, but every now and then, having an episode of worry may come with the territory of mothering and loving your family.
I think there are lots of people out there who deal with the unpredictability of life through imagining scenarios and how they would react. There was a popular "Worst Case Scenario handbook" series years ago, if that is any indictation.
Aside. We had a burglary this summer when we were home and when I woke and heard the intruder coming towards our stairs heading up to our bedrooms, because I had envisioned the scenario before, I was able to make a split second decision to wake my husband and immediately move a very heavy dresser in front of a door to protect our family (The burglar had knocked the phone off the hook). The noise of the dresser being moved probably sounded like a 400 pound man running down the hall and scared him/her away. BTW, this was avoidable. We learned not to leave windows open in the summer, the hard way.