Hello dear Understand your concern. It may be pregnancy if you have unprotected intercourse. Please confirm by pregnancy kit, 10 days after missed period. Following are the other causes of your problem: High level of stress, Change in life style, Late ovulation, Excessive weight gain/loss, Drugs: Birth control pills, thyroid medication, Excessive tea and caffeine, Thyroid problem, Hormonal imbalance, endometriosis, endometrial dysplasia. Take following advice: Do regular walking and exercise. Eat healthy diet Drink lots of fluids 30 min regular walk Apply Ice pack Relaxation exercise: breathing technique Low fat diet High fiber intake Decreased salt intake Multivitamin intake Reduce alcohol and caffine If period will not come , consult the gynecologist and do proper investigations: Also note that Menstruation required co ordinate action of various hormone that secreted by ovary (estrogen and progesterone) and brain (FSH and LH). If any above hormone is decreased or increased there is imbalance in menstruation. So please do full hormonal profile : Estrogen, progestron, LH, FSH, HCG and thyroid hormone. That help to diagnose hormonal imbalance. Abdominal USG, Endometrial biopsy, Ovarian follicle study. After confirmation you can take treatment according So please go ahead. Hope this may help you All the best. Stay healthy. Best regards Dr. Sagar