I feel like everyone and their mother is having a pregnancy scare and 9/10 times they take a pregnancy test days before their expected period. If a few days has passed after the date and still no af then test AFTER your expected period and check every week or so till af comes or it's been two weeks and you're now sure it's a negative. It's common sense. I get that you might be freaked out or it's sometimes irregular but it's a no-brainer. Also; if you have sex, have some kind of protection. Doesn't take a genius to know that.