This might sound dumb but I’m young and scared and just need like assurance I guess

Okay so I’m 16, and I lost my virginity around a month ago. It was close to the time my period was due, and I had protected sex, like, we used a condom every time and he pulled out every time and they didn’t break BUT, my period came like a day or two later and it was very short but it was heavy and had clotting... so I thought, okay, I’m safe I think. (My period was on July 5th thru 7-8) and I’m told having sex can change your period sometimes ? Idk, BUT today I had like very light brown spotting and I’m terrified that I might be pregnant and I don’t want to tell my mom because I’ll be in so much trouble if she finds out I’ve had sex... I just want to know if this is normal? My period is due in like 6 days according to this app. I’m sorry if my grammar and punctuation is bad, I’m just trying to get everything down.