I have been experiencing severe bloating, distension and feeling of fullness for several months. Rapid weight gain, fluid retension and chronic constipation for years. 6 weeks ago my doctor began treating me for possible IBS, started on Amitiza. I experienced severe diarrhea, however could not evacuate my gut regularly. I would take the higher dose 2 times/day. Took 6 days to have BM. There was so much fluid in my gut. After weeks of this, I was switched to Linzess, I have been on this for 5 days, although i have a BM within a couple hours of doseage, it is bloody diarrhea. Can you suggest what the underlying conditions may be. I have done some research and not all good outcomes. I did call my on call doctor this morning and was instructed to stop medication immediately. And to go to the ER if I experience another BM today with blood. However, if it is just a side effect, should I just wait til Monday, and talk to my regular Doctor.