Letrozole 5mg success

Has anyone had success with letrozole 5mg?

I’m currently on metformin 2000mg, coq10 400mg, a prenatal and now letrozole 5mg and am not sure if it’s working. Was there any signs you maybe had that it was working? I started with 2.5mg of letrozole for 3 months and they upped the dose recently. I never got a positive opk. I also have PCOS for reference with normal periods