in early years after menarche
in few girls menstrual irregularity can be seen, your condition is called
it mostly occurs due to hormonal
fluctuation which can usually settle down with progression of age,
at present you better consult gynecologist and undergo general examination to rule out other cases of heavy bleeding like thyroid
then with her advice you can go for oral hormonal pills either low dose combined or progesterone
only pills which will cure the present problem by suppressing natural hormones and leading to withdrawal bleeding.