I suddenly became very gassy and i had a bowel movement and i am still very gassy. some farts are smelly and some aren't. what's causing this?

Being gassy.: Being gassy in a sudden sense, meaning starting suddenly and ending suddenly, would usually be related to something you ate recently. Maybe something with a high fiber content to which you’re not accustomed. If it’s stopped by now, great. If not, or if any other symptoms have developed (nausea, vomiting, diarrhea), see a doctor.