YEP...the same exact thing happens to me! I have Crohn's and IBS. I am always constipated and I am taking Amitiza which helps great but I get those episodes right before I go. about 2 days a week this happens to me and I feel like either I am going to throw up, pass out from the pain, or just die. My face gets very hot and my face starts dripping from sweat. After the episodes I am freezing but my stomach pain is gone. Sometimes I have to sit on the toliet throughout the day before I actually get to go which makes it worse because the pain does not go away until I am able to go. Starts off with normal bowel movements and then dirrahea. I tell my GI this all the time and he acts as if I am the only one that has this problem. Never has a reason or anything. I have not found anything that helps at all. I just take the pain and hope it goes away quick.
Good luck to you!