Could fertilization have occurred?

If you use Vines tablets regularly, without omissions, every day - then protection against pregnancy is at a very high level, so a small amount of preejaculate should not cause fertilization. Diarrhea and vomiting pose a threat to the effectiveness of contraception, but in a situation where they occur up to 4 hours from the moment of taking the pill - in your case more than 7 hours have passed, so there is no reason to worry. If, despite everything, you have doubts, I recommend taking a pregnancy test after 10-14 days after intercourse. In my opinion, however, there is no reason to worry. I encourage you to familiarize yourself with useful materials: https://www.gdziepolek.pl/artykuly/jak-prawidlowo-stosowac-antykoncepcje https://www.gdziepolek.pl/artykuly/jakie-leki-oslabiaja-skutecznosc-antykoncepcji https://www.gdziepolek.pl/artykuly/czy-jedzenie-i-picie-obnizaja-skutecznosc-antykoncepcji