I had a Colonoscopy procedure 2 months ago with good findings but I been severely constipated right after.. Taking some laxatives which I did not take before did not help. My regular BM before the procedure was usually at least twice/day. I still am able to have BM daily but very very hard and I almost faint each time and I would usually sit in the toilet for a long long time sweating. I haven't change my diet, I take lots of fluids, eat some roughage. What could have caused this?