In the last week I've heard a couple friends reporting similar illnesses. I'm thinking it's the usual winter outbreak of Norovirus. AKA "Winter Vomiting Disease". It's a short ride: Usually a day or two of puking, then you're clear of it. The trick with norovirus is that it gets into food, but it can also just hang out on any old surface when the air is dry (hence, winter). So in addition to getting food well cooked, plain old-fashioned hand washing is a key to stopping its spread.