my DPO keeps changing

L • Sat, Oct 08

I keep missing the day AF is supposed to come according to glow so when I check my DPO it keeps going backwards. This is all so confusing. I guess that means I didn't bd during my fertile window like I thought?? I tested at "12 DPO" the day AF was due and that was 2 days ago, but today it still says I'm 12 DPO!