Need help getting rid of my belly?

ok so i have had a belly ever since I was like.. 8. anyways i am now 18 and i decided i want to make my stomach flat again, however the problem is im only 110 pounds, and i am 5'6. i realize i dont weight that much but trust me i eat pretty healthy and im in good physical shape. my resting heart rate in 55-60 beats per minute, i run 3-4 miles 5-7 times a week. anyways my question is how on earth do i get rid of my belly without losing anymore weight? i dont wanna lose weight cuz i dont want to be underweight, but i wanna have a flat belly. is there anyway? or am i just genetically this way and meant to be dispoportioned? :(. for the record i dont eat fast food, i dont drink pop, only water, i dont eat simple refined flours, only whole grains (brown rice, whole grain pasta, whole grain bread, etc...) and i eat lots of fruits and vegetables and lean meats.