Should I take the Plan B pill?

You know what I was not thinking about that. Thank you for putting that in my mind. Now, this might sound dumb, but do you mean as in ovulating? Because the day of my ovulation was on the 23rd, and I have this app where it tells me that there was a chance for me to get pregnant on the day I had sex.

The only emergency contraceptive pill proven can prevent pregnancy during the 24 hours around actual ovulation, is Ella (Ulipristal Acetate). You can see that on the Manufacturer's website.
Plan B might help, but it's not been proven.

For that reason, if you felt the need to take either, I'd suggest Ella.

Your menstrual cycle, runs from the 1st day of your period, until the day before your next period.

The fertile time/window of your
menstrual cycle, is your day of ovulation (a few hours long), & the 5/6 days leading up to that time.

If you are anywhere within your fertile window, here in the UK pharmacists are instructed to prescribe Ella, not Plan B.

Apps are just a guide as to where you are in your menstrual cycle.

If you think you may have got sperm or precum outside of the condom, such as on fingers that then touched your vaginal area, then you may want to use Ella. If not, then, as the condom didn't slip or break, it sounds unlikely that you'd become pregnant.