Woke up one night with really bad abdominal pains. Hurt so bad that I stood up on the side of the bed and went immediately to the floor and curled into a ball. It was just really bad diarrhea, but man my intestines felt like a war zone.
Another thing that I'm sure many on here have experienced is bad acid reflux. Waking up coughing in the middle of the night and having the back of your throat feeling like hot grease is never fun. I'm usually up no less than an hour waiting on the burning sensation to go away.
I've got bad acid reflux and it's horrible when it gets in your upper throat and nose. I've vomited because of it quite a few times.