I had my period on the 18th of august and everything was normal , i had unprotected sex on the 29th of august , today is the 4th of september and after i wipe after urinating i see pink i know my period isn't due until the 15th what could this mean ?

Very common: 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. Infections ; hormonal changes can cause spotting. If there is a concern for pregnancy then do a home pregnancy test . There are many options available to help regulate the menstrual cycle. Schedule a visit.