Emergency contraceptive??

So last night I had unprotected sex and I’m not sure if I should be worried about getting pregnant or not. <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says my period should start in 6 days, and you ovulate around 14 days before your next period. However, my periods aren’t down to a T and often come at different times, whether it be a week late or I skip a month or so completely. I guess I just need some reassurance and advice?? Plan B is expensive and I honestly don’t have time to get to town this week to get it before it’s too late to take anyway. What should I do? What do you think about this screenshot? That’s the kind of birth control I would have access to if I decided to try taking multiple of those.