sex & period

i posted about this the other day, my boyfriend & i don’t use any type of “birth control” besides pulling out when he feels, you know, we are so paranoid about something happening we even stop every couple seconds to wipe pre-cum off. my period is three days late, him & i are both freaking out. we are SUPER careful. even though we don’t use condoms or birth control, like i said, we check & he pulls out at least a minute before he feels it. today, we had sex, MULTIPLE times, & i had cramps before we had sex & after each time we did, can having sex help your period come or should i take a pregnancy test soon? i also read on someone else’s post, that sometimes you can get your period & still be pregnant. is this true ? please help me, we are both still pretty young.