Suggest Treatment For Heavy Menstrual Period

Hello, i am 12 years old and i started my period last summer. Ever since my first period i have been extremely heavy. I have to wear thick, extra long, jumbo pads and with that i have to put 2 on. I have recently started wearing 2 pairs of knickers also because they are so heavy i seem to leak through all my protection. Although they are heavy they do only last for around a week and by the end they are pretty "normal", help ?!