Anyone else dealing with/dealt with irregular periods or long cycles postpartum?? When do you poas?

I'm on my second cycle since my period started again; my second period started after 36 days, and I'm on cycle day 39 right now. I really don't think I'm pregnant (using condoms) but I was always super regular before lo2 with like 27 day cycles so this is really weird! We aren't trying but I have 1 test leftover that I'm tempted to pee on...