I rarely get my period and i'm 17, i masturbate clittorial and noticed after i masturbate i bleed for 4-6 weeks and currently i'm losing so much blood?

See your doctor: The lack of periods means that you are not ovulating. When you do have a period you have a huge build up of endometrium from unapposed secretion of estrogen. The masturbation has nothing to do with this. You can take fertility pills every month to cause ovulation, take birth control pills to regulate your cycle, or provera (medroxyprogesterone) for the last 10 days of your cycle to have a withdrwal bleed.