Three weeks ago I started feeling a change in bowel habit. My stool turned to a diarrhea for a whole day, then the next day it became as normal as before. At the end of the week, it turned into diarrhea again, which lasted for a day. At the beginning of this week, diarrhea lasted for a day and half, with abdominal pain, especially when sleeping. My stool turned to normal again and these pains were gone. However, today I have a constipation with abdominal pain. I'm not sure about the nature of it but it is the first time I experience such quick changes.