Could I have gotten pregnant from precum?

MY bf and I were naked and he wanted to do anal but while we were doing it he stuck his penis in my vagina to get more wet and he had pre *** on his penis. There was no penetration but im still really worried that the pre *** could have gotten me pregnant. He came in my mouth but is it possible to get pregnant if some sperm leaked into my underwear? Im very scared so if anybody could put my mind at ease please help!! Thanks so much