Thinking about living conditions over the end period, days or months would probably be no big deal. Days - nobody has any time to do anything or just shock. Months and half the population wouldn’t believe it or would go on as if nothing were to happen.

If it were weeks, though - that’s a tough one. I would probably hoard a bit then seek out a common meeting point for family to converge. Look at the comments here - everyone is tapping out. The reality is that a duration of weeks (say, 2-4) is short enough that certainty is high so most people would believe it, and just long enough that the entire fabric of society would break down - distribution networks, transportation, police, services. We saw how things went to hell in a handbasket when the first lockdowns for Covid hit. Trash will pile up. Store shelves will empty. Any service requiring human interaction to run - trash, power, water, sewer, public transportation - probably left without operators, probably not shut down gracefully.

I’ve actually had a minor 3am panic /nightmare about this - if the shit hit the fan, would I have enough gasoline in my vehicle to pick up my daughter at school and bring her home? (college student, 300mi away).