Prolonged menstruation could be a sign of underlying hyperplasia or pcos or fibroid..you need to get yourself investigated..do a ultrasound pelvis and serum
TSH as a start..consult back for further management..Also start a haemetinic like mumfer D3 once daily so that you dont become anemic..
If you found me helpful..please spare 2mins to write a feedback on this link..thankx
http://www.practo.com/ghaziabad/doctor/dr-astha-agarwal-gynecologist-obstetrician/feedback