I've never had any sexual activities ,but when i lie on tummy it feels like im lying on a ball , just finished period cant be pregnant, ibs?

Abdominal distention: You have to have a full physical examination to find out why your belly is distended. IBS is a diagnosis of exclusion. That means that other possible causes for abdominal dis tension have to be excluded. You might just have a excessive intestinal gas production. Try to avoid food that can cause it, such as all legumes, onions, cabbage, corn, milk products (if you have milk intolerance)