I was recently sick with stomach flu and i ate pizza today and now i'm passing gas every minute. is it just from pizza or because i was sick?

Probably both: It's common for people who normally tolerate milk to have gas, cramps, loose stools, etc with milk, cheese, etc after viral gastroenteritis ("stomach flu"). The infection reduces the intestinal enzyme lactase, which digests milk sugar. Poorly digested milk gives intestinal bacteria a feast -- and wheN THEY digest it, acid and gas are produced, with symptoms like yours. It should improve soon.