Progesterone and number of follicles

Hi there! I'm not sure if this is the right place to post this but I'm wondering if anyone can enlighten me on the relation between progesterone levels at CD 21 blood work and the number of follicles released after trigger shot! I had my second IUI last Sunday ( had 4 follicles mature at time of trigger!) and had cycle day 21 progesterone check with results at 18.49! First IUI, I had possibly 2 mature follicles (at most) at time of trigger shot and had a progesterone level of 28 at CD 21! Just curious if anyone knows if the lower progesterone levels indicate that not all of the follicles released? Or am I totally wrong?! First post here so please be gentle! Thanks in advance!