My Period Has Been Very Heavy, Please Suggest

I'm 19 and I have been taking birth control for about two years now. I am usually very regular when it comes to my period it usually starts right on time (when i take the green pill) and only lasts usually about 4-5 days or less. But this time my period started a week early (while i was on the white pills ) and I just started my green pills last night. My period has been very heavy and it is usually only heavy the first day. I have been on my period for about 9 days. I haven't missed a pill so why would it start early and is there something wrong if I'm bleeding more than normal and its been this long? If so should I go see a doctor? If so, what could be wrong? -thanks