very late period

so this is a really dumb question but it’s been bothering me. i lost my virginity around 5 days ago and my period was already 3 days late. i assumed it was just irregular (even tho it’s usually pretty exact) but i was unsure if he used the condom correctly so i took plan b anyway. i still haven’t gotten my period (now 8 days late) and we’ve had protected sex twice after the first time. i started birth control the day after the first time (to avoid future issues). i don’t know if my period is just weird because of stress or whatever but I’m really worried that i somehow am pregnant. should i be concerned or is stress just delaying my period? pls respond i know I’m paranoid but I’m genuinely freaking out. I’m 17 and not trying to start a family.