Letrozole Failure with no known issues??

I have very regular cycles (26-28 day) & my husband & I are very healthy & not overweight or underweight. We eat relatively healthy & in our late 20’s. Have been trying on our own for 9 months with no success so I go in this cycle which ironically began on July 1st & they prescribed Letrozole 5mg CD 3-9 & I went back on CD 12 for follicle scan & had at least one that was a very good size so I received the trigger shot. I went for my progesterone level check yesterday but won’t know the results until this coming week. I’ve tested the trigger out of my system, no longer showing a positive test with FMU.

I’m in a funk lately. The more I try to not think about it, the more I think about it 😰 I’ve been very tired for several days & I get plenty of sleep each night. For the last three nights I’ve had extremely odd dreams that make zero sense & I remember the majority of them!

My question is, anyone ever been so regular with no known diagnosis yet not conceive on their own nor on Letrozole?