Like Amber, my IBS arrived very suddenly after I had finished nursing my third child (at 4 months) It occurs every four weeks lasting about one week. I have such severe pain in my bottom, always feeling if I want to open my bowels again. I am neither constipated nor have diarrhoea. I also have severe knotting pain in my central abdomen. I assume that the symptoms are hormonally related. So far I have found nothing that helps.