Progesterone level/letrezole

My husband and I have been trying to conceive baby #2 for 2 and a half years now. My first round on letrezole at 2.5mg I never got a positive ovulation test. This second time around i got put on 5mg. I got this as an ovulation test a week ago I think it is positive? But I went in this morning for a progesterone test a week later and this evening I went to look on my medical chart and the results say 4.0 no/mL. Sounds low to me but I'm not sure. Anyone have any advice? My doctor should call me tomorrow or Thursday but I'm impatient and was just wondering if anyone knew anything about these progesterone levels. Thank you in advance ☺️