Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have symptoms of delayed periods along with severe abdominal cramps and diarrhea . Well there can be many reasons for symptoms you mention in query like consuming foods such as sea food and nuts , appendicitis, crohn’s disease, gastroenteritis, irritable bowel syndrome or urinary tract infection. If condition doesn t get well then consult gastroenterologist for proper examination . Doctor may order ultrasound , endoscopy along with stool test . Doctor may prescribe laxative , anti inflammatory along with antacids . Delayed menstrual cycles along with severe abdominal cramps and diarrhea are suggestive of some disorder associated with hormones or some abnormality in reproductive tract like fibroid etc. I suggest you to consult your gynecologist for clinical assessment and investigations like ultrasound abdomen and assessment of hormones to know the cause of symptoms. It is always better to go for a beta hcg,a blood test to detect pregnancy. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari