Progesterone levels?!?

Anna
This is my first round of letrozole (femora). All went well after taking it. I just had my cycle day 22 progesterone levels drawn. My number came back at 18.5. Is that good? Not feeling any symptoms other than very mild cramping the last few days ( almost as if I'm getting AF). 8dpo, AF is due in 5 days and I'm PRAYING I don't see it!