Progestion levels

I have had a miscarriage a couple months ago. So my doc keeps tabs on my progestone. The first time it was 26. Then it dropped to 24. And got tested again and I am 6 weeks now. And it dropped down to 22. Is that bad or normal. She did say as long as it is above 14 that's good. But naturally I get worried. Cause of me miscarriage last time