I havent had my period for 3months and then i started bleeding very lightly for 2days and stopped on the 3rd day.. what is going on?

Common problem : 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 redo a home pregnancy test . There are many options available to help regulate the menstrual cycle. Schedule a visit.