What Causes Abdominal Bloating And Loose Bowel Movements?

I have experienced a change in bowel function within the past 2-3 weeks that I am concerned about. Instead of having regular bowel movements of normal consistency, I started having bowel movements that were more loose than normal (though not loose enough to be considered diarrhea). Then, the condition seemed to switch back and forth from constipation (sludge-like bowel movements) to loose bowel movements and I feel very bloated and gassy. What could this be?