Still no AF

GirlMom💝 • Wife/StepMommy/Mommy of 2! 1-31-18 & 7-18-20❣️
AF has yet to arrive! My BBT dropped drastically this a.m. it went from 97.09 Saturday morning to 96.61 this a.m. What could this mean? I take BBT around the same time every morning. I also whipped last night and a very thin line of blood was in my discharge but so far no sign of AF? Whats going on?! Nauseous for the past couple of days but no sore breast yet..!