What Causes Vaginal Bleeding While Having Ovarian Cysts?

Hi I am 24 years old and the day after i had sex with my husband I started having this really dark sandy looking bleeding. Its been three days and i still have it like a period but it could not be because it is two weeks early and i am on birth control. i had a pap smear done a month ago and it was normal. i had a sonogram and it showed that i had cysts on my overies and my doctor told me not to worry about it. Now i am bleeding and i don't know what it could be or what else to do from here.