3rd IUI 😞

So I'm doing a 3rd round of IUI this month. I've started taking the letrozole again as well. I don't know I just can't get excited and hopeful this month. It's been a year that me and the hubby have been trying. I'll be 36 next month and I just want to be pregnant already!! Sometimes I don't think my body knows how to get pregnant. Has anyone had better luck with multiple iuis? My doctor won't do any more than 3, he says after 3 it won't probably work.