I have always suffered with painful periods and was put on the mini pill last year. This has completely stopped my periods but every now and again I have sever bowel pain. I used to get this on my first day of my period, every other month. I'm still getting this even though I am not having periods (however its only 3 or 4 times a year now) so I know what I experience is not diet related.
So I would get the normal amount on discomfort anyone would get when they are about to empty their bowels, but once I get to the toilet that changes. I go all weak and my pain comes and goes in waves. It feels like contractions that last a few seconds and then fade away, and it gets more painful each time. After the intense pain eases off soft stool would come out and the pain will build up again. By about the 6th wave of this, the pain will be unbearable and I will start sweating from every pore on my body and will become extremely nauseas and faint. Some times are worse then others, most months I experience mini versions, where It stop after 3 or 4 waves, and I would be okay. But every now and again I would have the extremely painful one I just described. Afterwards the pain will stop and I would be left feeling exhausted.