Birth control??

Okay so I got back on birth control just a few weeks ago and it’s a stronger version that I had last time. The week before my period is when I started bc but I expected to still get my period. I’m on week three and just started the placebo pills in the month that you’re supposed to take with your period. My bf and I had an incident about a week before bc started and I’ve been incredibly paranoid about pregnancy lately. I bet I’m not pregnant but I need some reassurance ladies. Please tell me this is normal