Frustrated And Confused

I am 26 years old and am an RN. I need some answers and I can’t seem to find anything that even sounds like my problem. I have been on birth control pills since I was 19 due to irregular periods, heavy cramping and bleeding. I got married at 21 and we decided last October we would come off the pill and try to get pregnant. I was off the pill and on prenatal vitamins last October. My last period was December 9th. I found out I was pregnant Jan. 9th but my HCG levels were so low they told me I was “mildly” pregnant. I had them re-checked three times that week and they did double but slowly. I was spotting off and on. I had multiple lab tests and all my HGC levels turned out fine, they kept doubling and rising. No morning sickness but all the pregnancy signs and symptoms. I spotted off and on for the remainder of the pregnancy. I had multiple vaginal ultrasounds done. Heartbeat was found on Feb. 7 and they moved my due date back hoping it was just a pregnancy found early. I went back Feb 21st. No heartbeat. My body was holding the pregnancy fine other than spotting. The OB told me to have a D&C because my body was going to hang on to the pregnancy as long as it could. I had the D&C Feb 21st of this year. I bled and spotted for the next two weeks. Had no period in April. May’s period started around the 6th and last 6-7 days. First with a lot of brown to black tissue and then light bleeding. June the same but lasted eight days. July started around the 4th and lasted nine days. August started around the 4th and lasted nine days. September started on the 3rd and lasted twelve days with same tissue to begin with and then brown red blood started and stopping, sometimes not even enough to wear a tampon. October started the 1st and so far has lasted eight days but I’m still spotting, having a lot of dark tissue. The whole time we have been trying desperately to get pregnant again. We both want to start a family. We’ve been trying eight months now since the D&C. I switched OB because I wasn’t getting any feedback, any answers, anything at all from my other OB. Not even when I discovered I was Rh- and they had not immunized me with the Rh immunoglobulin did he have any answers or comfort. I’m not sure if a D&C can cause hormonal imbalances or if I have scar tissue or retained pieces of the preganancy or what but I need some answers. This new OB wants to start me on Prometrium 200mg, one PO QD day 18 thru the next 12 days of the month to see if that will decrease the length of my cycles. Everything I’m reading says that that will also interfere with ovulation and that’s not what I want. I’d rather have long periods than chance another month go by that I don’t have a chance to get pregnant. Should I try this? I’m really confused because if I ovulate sometime between the 16th and the 20th then the Prometrium may cause the egg not to implant right? I don’t know why she’d give me this medicine if it could actually hurt my chances of getting pregnant. She didn’t draw any hormone levels and I’m just frustrated and confused. Can you help answer some of my questions? And if I take the Prometrium after ovulation and I only have 12 days worth won’t that drop in progesterone cause a miscarriage? PLEASE HELP!
Robin