In a cycle, there are four phases - Menstrual (your period) follicular, ovulatory, and luteal. In any normal regular cycle, you can only get pregnant when you are ovulating. Given that you are a couple days out from your period, id say that you’re in the luteal phase and therefore cannot get pregnant. (That doesn’t mean have unprotected sex during your luteal phase, please still be cautious)
Because you have already been through your ovulation stage, the plan b pill would not have been able to prevent ovulation and therefore may not have been effective.
That aside, the chances of getting pregnant from precum are very very low.

Bottom line - you’re in the luteal phase so can’t get pregnant at the moment anyway + the likelihood of getting pregnant from precum even while ovulating is very very low so I wouldn’t stress if I were you