Should I take Plan B

So, last night/this morning I lost my virginity! Which is great however, we didn't use protection because it was kind of an off the wall thing but he also didn't cum nor I because I kept stopping him because it hurt too much (I'm having issues relaxing which is a whole different issue) and now I'm only a little bit nervous what maybe I should grab Plan B because I'm not in birth control and he has orgasmed earlier that night. I just know that you can get pregnant from precum and so now I'm only slightly worried! But worried enough! How likely do you think it is that I could get pregnant and should I take Plan B?