My period starts in a week yet I'm spotting light pinkish brown as of today wednesday and I had unprotected sex monday what is the reason its early?

Common complaint. 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.
Implantation Bleedin. If your unprotected sexual activity was during your ovulation this is implantation bleeding of the impregnated egg on the side of the uterine wall.