I think I’ve got it.
Then you're already halfway through the whole event. And still sitting at your computer! We 'enjoyed' it years ago in Germany courtesy of a Turkish Doner joint, and the while lasted about two days.
The Friday prior to Christmas five of the people in my office went to the restaurant next door. Four of the five had it coming out both ends Saturday and Sunday. It was about a 24 hour delay. So, probably not food poisoning. Plus, they all ate/drank different things.
About fifteen years ago my company had a party at the local country club on a Saturday night. Myself and literally half the attendees were sick Monday morning. I missed two days of work. The local health department shut the place down. They cleaned it for two days. The interesting thing was at our table of eight all the men got sick. All the wives were fine.