Hi M., I 52 but when I was in my 30's I also had several miscarriages. I and experienced missed periods, the first time was for three months I also got negative pregnacy tests results, after three months my period did start and I bleed for about 3 months, it started with spotting and got a little bit heavier each month until I was almost hemorraging it did not stop on its own.
I finally went to my doctor because I was getting light-headed and my heart would race everytime I climbed stairs,(I had become anemic from the loss of blood), my problem is fibroids, I am on prometrium 12 days a month to try and keep my periods normal. Also I have a friend whose daughter is about your age and she also had similar problems which were caused by fibroids.
Also if you are in need of inexpensive health insurance I may be able to help you.
Hope this helps,
Franny