No period and BFNs? What?!

S • 🇬🇧👰🏻🧔🏻👼🏻👼🏻🌈👶🏻Due Nov ‘19

Hi guys, just looking for any theories here? I’m a regular 28 day cycle and today I’m 3 days late. I tested on the first day I was late and it was a negative (clear blue digital).

Any theories?