How To Treat Irregular Mensuration?

Hi. I am 23yrs old and from last two years facing a problem with my mensurations. For the first year it was not at all happening; in that yera twice i took medicine from doctor and after taking the it was coming only for that month but again it was was not coming. But from last 9 months it coming for 2-3 months continously. Its not stopping without taking medicine.The flow is very heavy and in after every minute i can see a big blood cloet. Could you please tell me which disease it is and what should i do?