Progesterone question, please help!

Jess • Mom of three and currently expecting boy/girl twins! 👧🏻👦🏼👦🏻👶🏻👶🏻

CD21 progesterone was 13.18 dr said it indicated I had ovulated, I went in at CD29 for a quant test and they checked my progesterone too, my progesterone came back at 27.88 and quant was negative. I’m just confused because I thought progesterone was supposed to drop at the end of my cycle, AF is due on the 14th