Plan B caused missed period???

Ruby • God 1st ✨| Lani’s mommy 👶🏽💕| J.O 💍| 21 | KU 📚 𝐸𝓋𝑜𝓁𝓋𝒾𝓃𝑔 🐛...🦋

Hey. So I took a plan B on January 23rd. I got what I believe was my period a week earlier than it was supposed to. According to Plan B that’s normal. Fast forward a month later, my period still has not come yet. I took 3 pregnancy tests throughout the month, the most recent being yesterday, and they all came out negative. I’m a week late according to this app. I’m worried and confused. Can anyone relate or tell me what’s going on?