2nd round of Letrozole 5mg

Currently on my 2nd round of letrozole 5mg cd3-7 due to low progesterone levels and lack of ovulation. I did not get a bfp from 1st round but cycle was shorter/normal at 31 days as opposed to 40-55 days. At cd17 right now. I think I have O'd already but not 100% sure. ovulation test was getting darker and almost as dark as control on cd13 and then light on cd14. Just wondering how many rounds it took for you ladies to get a successful bfp?