Late Period

Hey everyone, so I need some advice. My boyfriend and I had sex twice in one night on December 3rd. My last Period (the last day) was November 24th. Both times we had sex, we used a condom, he pulled out, and we checked to see if it tore at all. I wasn’t worried until recently. According to my tracking (which I’ve been doing for months now), I’m two days late on my period. Now I know <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> isn’t always right on target, but because we had sex I am concerned. Anything I can do to ease my nerves? Or should I even be worried at all? Also, how effective would a pregnancy test be at this stage?