Help me :(

3 days ago, I'm having my first time sexual intercourse with my boyfriend (well that time I'm still a virgin plus my pussy tight tho) but it only takes around 2 minutes once his dick get into my vagina and he pulls off. Since yesterday, I feel like I'm need to frequent peeing but only small amount or sometimes there is no pee at all. Moreover, I can feel the pressure at my lower abdomen. Btw, he's not came that day or the day before or the 2 days before we're fooling around. Ive read some story that precum can make you pregnant so I am getting pregnant or what? But I don't even feel that I'm having pregnancy symptoms like what others say and it just I need to pee but there is no pee (I hope you understand what I mean). Futhermore, on the day when we're doing sex, that is day 21 in my period cycle and is it possible that I can get pregnant from precum? He also doesn't think that I can get pregnant because of he felt hurt like his dick is being squeeze when he's trying to put it inside me.