Began period on 3/12 should stop 3/17 however i had light bleeding all the way to 3/24 where it turned into a full heavy period like cycle. whts wrong?

Not normal: Bleeding in excess of your periods is not considered normal. However in a young and otherwise healthy woman who has never had this before, i'm not very worried. As long as your pregnancy test is negative, i would not pursue it unless it happens again. At that point i would see your gynecologist for an evaluation. Irregular bleeding can be from polyps, fibroids, infections, or hormone changes.