PrEP taken daily can be very forgiving of any missed dosages. Estimated
While stopping PrEP, after 30 days of daily dosing, the estimated protection offered by the PrEP remaining in the body from HIV transmission via anal intercourse was 97% 24 hours after the time of the first missed dose, 96% after three days, 93% after five days, and was still 90% a week later. (Source from AidsMap). This only applies to cis men. Cis women and trans men should not miss any dosages.
Even if you miss a dosage, you can still continue to take PrEP the next day. It is not necessary to take double dosage to make up for the missing dosage.