Can Stomach bugs effect people in different ways?

The other day I woke up and the bottom half of my stomach felt uncomfortable (a bit like it does just before you have diarrhea) I felt like this most the day, I didn't want to eat or anything. Then later on that day I felt a bit better. So i went out for a meal with my girlfriend. After my meal I felt awful, My stomach was unsettled, I felt bloated, I felt sick. The unsettled stomach continued for the rest of that night and into the following day, As I didn't feel too bad the following morning I went to work. I wasn't sick and I didn't have diarrhea. About 3 days later, two students at the home i work in started to get a stomach bug and were being sick and having diarrhea. My friends are telling me that it was probably me that started this bug as I went into work with my unsettled stomach, but i find this hard to believe, because I wasn't sick, my stomach just felt unsettled. The two people at work were being sick. Do you think it is possible that this was a bug I had and i have ped it around. Does stomach bugs effect people in different ways?