Progesterone levels decreasing?

So I had a mc back in June and we are now 12w preggo. My doc has been taking blood samples every couple weeks because of last time. My progesterone level three weeks ago was 29.8 and last week I had more blood drawn which resulted in 26.5... But everything I read online says levels are supposed to rise as your pregnancy progresses yet mine aren't. The doc hasn't fully explained the results yet because I don't see him until Tuesday and the nurse only read me his notes basically. I'm so nervous and I want this baby to be healthy and not another mc... Anybody have Info on progesterone levels and if my drop is major or ok or what?? I'll go crazy waiting until Tuesday for info lol