What Causes Prolonged And Continuous Menstrual Bleeding?

I'm a five foot three female and weight 113 pounds and I am 18. Over the past ten months I have had a non stop period. I was on the Depo shot for along time to try and stop it when I originally had this problem in the seventh grade. Has haunted me ever since. Maybe related, I can't get "wet" when I'm turned on at all which is another prevention of sex for me and my fiance. I have been taking birth control pills and they helped for two days and been back on for ten months. Please help me