What Causes Heavy Bleeding And Spotting?

I am a 26 yrs old Muslim women Nulliparous and I am married ,I had been experiencing heavy bleeding and spotting since 3 months now I want to go for religious rituals for 10 to 15 days kindly prescribe me The Dosage of Primulot-N Daily . I Know It has to be taken a week before menstrual cycle ,I had been taking it 2 years ago but I have lost my reports and have forgotten its dosage .