Bread causing stomach issues?

Hi guys, I have observed this that nowadays bread related food is causing stomach issues in me and people around me. Most of the people I know are living in Delhi NCR. And I have observed on multiple occasions that consuming items ranging from Dominos Pizza to thela bun makkhan, all are making me/my friends/family and knowns sick. Vomiting (in some cases) and bad stomach are observed almost the next day. Just wanted to know if someone else also faced something like this or is it just by chance?