I Have Ongoing Prolonged Menstrual Bleeding For Average Of 10-15

I have ongoing prolonged menstrual bleeding for average of 10-15 days per month. My cycle is also short of 15-20 days.
I have past hx of abnormal heavy bleeding and had undergone annual D&C since 2011 just to regularized my period. I fell pregnant in 2013 but had a miscarriage when I was on my 3rd month.
Now, I had again D&C last October 2015 due to a polyp. But after 2 months my period was messed up again. Due to frustration, I took alternative intervention such as taking Vitex, Premular, had an acupuncture and TCM. Still bleeding occurs long and every other week. I had my latest ultrasound which entails that my endometrium and ovaries are normal, my hormone levels are normal except for depleted iron because of the bleeding. The period only stops with Primolut. Now the doctor gave me Marvelon 28 and I'm still bleeding for 2 weeks. I wanted to fall pregnant one day but with this history, please advise me what should I do. I am so frustrated now with my haywired hormones.
I am turning 38 and only have one 16 year old child.
Thank you