I had unprotected sex on the 21st. Had unprotected sex the 23 again and took a plan b the 23. On an app it said I’m in my fertile week and I could have ovulated the 23 when I took the plan b. is it possible the plan b worked since the ovulation day is just an estimate or is it unlikely it worked ?

Side note: my periods are irregular so I don’t know for sure if the ovulation date was correct, just an estimate!