First IUI, ovulating later than normal. Anyone else?

So I went in last Friday, CD 12 for ovary scan after taking Letrozole. Follicle only 14mm. My RE had me come back today CD15 and he says no real change in follicle size. This will be IUI round #1.

He had me give a urine sample which was negative for LH surge. Wants me to come back Wed for another scan.

I just dont know if I can deal with this not working. My DH and I have been TTC for almost 40 months. We've been on Clomid before that resulted in a miscarriage and a chemical. I will be 40 years old in March with no children.

I guess I just need some encouragement. I'm just mentally exhausted.