Temp increase 3dpo?

Amy • Married since May, 2015 but with my soulmate since 2007. Gavin, was born at 36+2 on 6/21/16 is now big brother to Ryan born at 40+5 on 7/20/18!!
I've been using a ovulation kit and it showed peak fertility on 10/20 and I also had ovulation pain that same day...Glow said ovulation was 10/21 according to all other data I entered.  Not really much of a change in my bbt at all during this cycle until this AM.  What does that mean?