I hope this is what you mean by chemical miscarriages...
I had what the doctors thought to be an ectopic pregnancy...many symptoms of it, but levels did not get high enough for them to know 100% for sure. Basically, mine started out very low at 31 hcg at 4 weeks pregnant. (I never found out my exact levels for progesterone, but I know it was too low). By 7 weeks pregnant it had climbed to 81 hcg (no where near where it needs to be). After, many symptoms...brown spotting, vomitting, severe back pain,etc. My doctor gave me the devastating news that there is NO WAY I could continue carrying the baby. So, he gave me the choice of surgery or having Methotrexate injections. I chose to do the Methotrexate due to the fact that I would like to have more children and I did not want to take the chance at one of my tubes being deformed by surgery. The injections really hurt, but it was an easy process (physically - not emotionally). I didn't have any cramping, but I did basically have my period of the injections. My cycle went right back on track. The major downside was that I had to wait at least a few months to try and conceive again. Also, I do believe it stripped my vitamin levels in my body. I became Vitamin D and B deficient, but everything is back on track now. Anyways, that is my story - at least the short version. Hang in there, ask a lot of questions. I do think you should also ask your doctor about taking progesterone. Your hcg is nearly doubling, so there may still be a viable pregnancy. There is always hope. I will keep you and your family in my thoughts. :)