Progesterone levels

Ta
So I had blood done Wednesday and I got the results today. My OB started me on Prometrium before the results got in because of a previous miscarriage. My results for the progesterone a 10 and my hcg levels were over 84,000. She only prescribed me 100mg to be taken once a day. 
My question is, has anyone ever had their levels this low only to have them go up an have a healthy pregnancy? I'm so worried that my levels are too low. I've got another blood work scheduled for Wednesday to see if my progesterone has increased. Worried sick!