Hi, my husband and I are TTC. I am currently on Metformin 800mg, been on it since the beginning of October 2015. I've been charting using an app that predicts and my cycles have been perfectly in sync. October had a regular cycle, November had a regular cycle, and I ovulated right on cue. Was sexually active during my fertile window. Here I am 4 days late, but took 4 hpts and all were negative. I've been having kind of a tacky milky or pearly white discharge, nauseous, and having hot flashes. Could I possibly be pregnant?