I had an interesting thing happen to me a few weeks ago. Maybe someone knowledgeable about the human body can give a reason why this might happen.
I ate 2 fillets of fried catfish from my local discount grocery store...I know, probably not the best idea. 3-4 hours later I began to feel very sick, and I soon began vomiting. This lasted for an hour or two until I had nothing to vomit up.
At this point, I was kind of hallucinating/dreaming...constantly being between awake and asleep (like when you get a bad cold and can't sleep at night), about me owing an auto shop. When I was fully awake, I had the uncontrollable urge to drink water. I would get out of my bed and fill up a glass of water and chug it. I remember that it tasted so good. After I was done, a few minutes later I would get another glass. This would continue until I began to feel sick from drinking so much water. Eventually I would vomit up pure water because I couldn't stop myself from drinking more water.
After I had vomited, I would feel better for maybe 30 minutes, then the cycle would start again. I probably drank 2 gallons of water, judging by how full my trashcan was of water-throwup.
Why would this happen? I would be interested to know!