Lower abdominal pain and bleeding

I am 19 years of age and am sexually active. I have not changed partners. I do not have any sexual transmitted infections. I have the mireena coil fitted and do not have periods any more. I get very sharp stabbing pains in the left, right and middle of my abdomen. This pain is as low down as my pelvis. I had a ultrasound scan which showed folicoles on both my left and right ovaries. My blood tests to check my hormones have come back normal. I had this pain before having the coil fitted. In the last 3 months I bleed every two weeks for no reason and sexual intercourse is now painful. I have not changed the things I eat or drink. I am in so much pain that sometimes I cant move and only a hot water bottle helps. I have taken painkillers with no results. I am desperate for answers and my doctors do not seem to have any for me at all. They have not ruled out endometriosis (sorry for the bad spelling)and say that if I do have polycystic ovaries then it isnt effecting me as im not overweight or hairier then normal and it will go away on its own. At the moment I am thinking the worst and worrying that I may not be able to have children in the future. I would be extremely grateful if anybody could give me any advice or any kind of information.