Missed period

Me and this guy kinda sorta had sex i guess. We both knew that we didn't have a condom but we were just messing around and he put it in for just 2 mins and he pulled out and something bout it's just pre-cum. Now I missed my period by 11 days but I have I have an implant which is one of the best birth control but I still haven't gotten my period and I'm freaking out😔 please help.