I don't want to scare you, but I really think you should go get that checked out. My sister has a friend with ovarian cancer, and apparently that can be one of the (very few and vague) symptoms. Now the chances that you have cancer are VERY SMALL!!!! ... but because it's on the list of symptoms that could lead to something serious, I'd say you should at least go in and request an ultrasound of your abdomen.
Then at least you'll know once and for all why your tummy sticks out a bit!