once go for ultrasound
of abdomen and pelvis done so that we can rule out cause for your cramps and heavy bleeding.you didnt mention your age,are you married??
heavy bleeding vth pain may be due to fibroid(tumor
like growth in uterus
),or may be due to endometerosis..go for ultrasound and urine test for confirmatory.
if frequently your suffering from heavy menses than you can be anemic so better get that test done soon.