Hello, I have gone through your query and understood the concern. If you have always been regular with your cycles and sexually active, this menstrual delay is suggestive of a possible pregnancy. Other causes are hormone imbalances out of sudden weight disturbances, ovarian cysts or stress, infections and certain medications. In this scenario, I would ask you to see a specialist for proper clinical evaluation, a trans-vaginal sonogram to know the status of the pelvic organs and urinalysis to exclude any UTI. Further management can be planned accordingly. Hope this helps.