What could bewrong w/my stomach?

After I go to the bathroom,it's like my colon empties too fast. Rt after I go,I start puking up stomach bile,sweating,and it radiates to my lower back & hips. And no pain killer helps. I usually have to go to the hospital to get hydrated by 2 bags of fluid through a IV,because I can't hold anything down. Not even water. Someone said maybe Chrons. I've had many tests done,they can't find it. Help!