AF is 12 days late, negative HPT, and entering fertile window

So my AF is 12 days late which is really unusual because I'm usually on time or 1 to 2 days late Max. Took a HPT 2 days before, 3 and 6 days after but all came back negative. I booked a doctors appointment for blood work but not until next week. 

Tomorrow is when my fertile window starts, my question is, if I am not pregnant and for whatever reason skipped my period last month, will I ovulate according to Glow? Should I BD for the next 5 days? I'm so confused!!