23 and disappointed 😔

My husband and I have been TTC for just over a year now and to say we are disappointed is an understatement. We have one son together who will be six this year, so we thought getting pregnant again would be a breeze. We've had all of the tests done and our next step is IUI. At this point it is pretty unexplained as to why we are failing. His semen results came back a little low, but they didn't mention anything about the mobility being off. Plus, we had to send in a sample during fertile time which was pretty inconvenient. The nurse said we needed to wait three days after intercourse to give the sample and we only waited two; let's be honest, I was having trouble wasting a round of sperm for testing when it could get me pregnant 😅 I'm having trouble coping and also over everyone saying stop stressing and it will happen. We are actually very low stress people. I don't obsess over keeping up with ovulation, bbt, CM etc.. anyone else?