OPK testing madness

I have a 36 day regular cycle and I don’t ovulate until cd 22 or 23. You may still not have ovulated

My peak lasts for longer than 24 hours, but it’s unlikely you missed yours, it’s still early but I would test twice a day. Good luck!

How many times a day are you testing and when did you start? You should be testing twice a day and maybe three times once you get closer. Sometimes my surge only lasts a few hours (for example when I got pregnant with my son, my 7am test and 9pm text were negative but the 2pm one was positive). If you’re on CD 18 I’m guessing you’re only testing once a day? You may have missed it this month unless you know you have a longer than average cycle.