Not quite as bad...

...as this round of Norovirus in a care facility:

I was not the first staff member to note either loose stools or vomit, but I was the nurse who called it an outbreak, implemented precautions, and got the ball rolling. It had been too late from that moment in the dining room when one resident vomited in the dining room.... The outbreak was exhausting. Nobody worked the entire outbreak. My usual night CNA was sick halfway through the second night. We paid bonuses to hospital nurses and techs who came over to work. I worked three nights in a row of either twelve or sixteen hour shifts, and then succumbed. (While I was giving report, I said, “Excuse me,” and went off and puked. I bleach wiped the staff bathroom, put on a fresh mask and gown, and finished report standing five feet from my colleague.)

The bug which we got gives warning before the projectile vomiting, and the diarrhea comes a bit later.

It's pretty clear that in our case, it came from the grocery store, in one way or another.