Hi,
I had an mc at 7-8wks in August 2009 and then two possible chemicals. After my OH and I decided to do IVF, we discovered in pre-IVF blood work that I had an underactive thyroid and once the medication/blood work was adjusted (started in January 2011, correct level in May 2011), I got pregnant natually in June and am currently 31wks+ and counting down the days to the 27th February (8 wks today!!!!) to meet my little boy. I was also given metformin for PCOS by my GP in September 2010 and believe that that helped me to get past the 12wk mark (can help with the formation of the placenta).
Incidentially, I was 41 when I originally mc'ed, after being told I couldn't probably have children, and was 43 when I conceived this little fellow. I lost weight, gentle exercise, tried acupuncture, the above medication and some other little things, but felt I just didn't have the strength to do IVF (and prayed/I'm spiritual not religious) and got pregnant naturally that month. I will be 44 when I deliver.
Please, please, please do NOT give up hope. Also, you could always consider egg donation/IVF or even adoption, so there are so many ways you could have a child!
best wishes