Waiting to test with irregular periods

Ashley

Hi guys, trying to conceive baby #2 (first time around I took progesterone to start my period then one round of clomid and became pregnant). My son is now 19 months and I tried a otc opk this month. Had sex on ovulation day (august 16th) and am wondering when I should take a pregnancy test. 🤔

I tried one yesterday and it was negative 😔. My periods usually come around every 40 to 45 days or so and my last period was the middle of last month.

Help!