Letrozole mamas question

How many cycles did it take for you to conceive using letrozole ? 3 months post mmc I took 2.5mg and got pregnant with my son first round . I got pregnant naturally in April but mmc at 13 weeks got pregnant 10 weeks post d&c and ended in chemical . I am now on my 4th cycle with letrozole , first two cycles didn’t work (I have pcos and annovulatory cycles) but last cycle 7.5 did but no pregnancy :( trying again with 7.5 . I’m losing hope let me hear your stories