Period thrice a month. first : 15-16 august. 26th protected sex. then 31st aug - 8th september heavy bleeding. now 15th sep bleeding agai. pregnant?

Irregular period: Irregular periods are one of the most common problems obgyns treat. If this is one time problem it usually resolves on its own. If this is a recurring problem you should be evaluated. There are many options available to help regulate the menstrual cycle. If you think you might be pregnant check then check a home pregnancy test. They are cheap, reliable and available at any pharmacy.