Letrozole round 2 failed

Hi ladies, I don’t usually do this but I’m feeling really discouraged… I just finished my second round of letrozole (5mg) (failed) my first round was 2.5mg and progesterone on cycle day 21 came back at 11.1, my second round was upped to 5 and progesterone came back at 14.9. I ovulated both rounds but no positive pregnancy test😢 I miscarried my first pregnancy ever at 8 weeks in February of this year. Any ladies who can share their success with letrozole or any advice you’ll can give me. I’m feeling so shattered.