In major pain?! Please help!?

Everytime I eat something, a cracker or a meal, I get "gurgly" stomach. Then,my stomach gets one huge cramp, and I'm writhing in pain. Then I go poop. I don't know why this is?! It just happened. Sorry if it's too much information but I don't know why this is. I am twelve, if that has anything to do with this.