What Causes Excessive Vaginal Bleeding And Tiredness?

For the past 3 months I have been having my period every 2 weeks, lasting 5 days each time. Now my last period started on 12/30/14 and hasn't stopped yet. Not sure what I can do to stop bleeding or if need to be seen by gynecologist or not and if so what are the possible things to be concerned about. Its basically just aggravating and making me more tired than usual.