Hey K. -
I can't really answer your question from the miscarriage point of view, I am a single mother by choice. I had my son when I was 32 by artificial insemination and then I had my daughter when I was 37 by the same method. I was lucky because I got pregnant on my first try each time. BUT, the point of this is to tell you that I had to see a fertility specialist to get pregnant in this manner. They offer so much information and advice and really do a thorough check of your situation. For my first pregnancy, because I was young, they did not do anything "extra". But because I was 37 the 2nd time and I only had two vials of the same father as my son, they got more serious and did sonograms and watched the progress of the growth of my eggs. Further, they did put me on the progesterone as other women have mentioned. The specialists are all about pregnancy and getting pregnant and could surely help you. I think it is at least worth going to talk to them - especially considering your age.
Also, as a single mom, it certainly would have been easier for me to just stop at one child. But, I felt this deep down urge to have another child. I did not want my son to be an only child. If you are having those feelings, I don't think they will go away. I think you will regret not trying again.
I saw Dr. Le in Irving. He was AWESOME. He was so nice and gentle and caring and his whole staff was very professional. The office was calm/quiet and clean. I loved it there.
-L.