Still no period, going on week 2

I mean honestly, I took a plan b the next night after the awesome unprotected sex. Forgive me! I'm allergic to latex. But I haven't had a period in 2 weeks and usually when I take the plan b's i have a period within days but not this time. Nu uuuh, so I need to know could this be a side effect. I tested negative on the pregnancy test 🤦🏽‍♀️