skipped period on the pill

So i’ve been on the pill since october of 2017 and i’ve never experienced anything like this. i take my pills roughly about the same time, usually within an hour of my scheduled time. One day i was about 20 hours late (i left them at my house when i was at my friends). the next day (my pill information packet says missing one pill is okay, and you don’t need a backup method)i had unprotected sex, but my boyfriend never came inside of me. i know for a fact he didn’t because i saw, but i know there’s a chance he precame and i know that still has sperm in it. i know i don’t wanna be worried i’m pregnant because the chances are very very low, but i can’t help but worry. i have 4 sugar pills and i’m supposed to take my first hormone pill again tonight, and start a new pack,

and my period hasn’t come yet. i’ve had no signs of pregnancy. no nausea, besides this skipped period. i feel like i’m having period cramps every so often but there’s no blood what so ever. has this happened to anyone? does anyone have any advice? Anything at all is helpful. thanks ❤️