Confused about ovulation day

Km • 27. Married 5 years. Our daughter Stella Claire is our entire world. Born Nov 15. 2015. Pregnant with #2 due in April.
I'm not using OPKs, just listening to my body. I've had signs of O for 3 days (EWCM, bloaty, cramps) but what day is actually ovulation? Glow only gives you fertile days but no predicted O day...is it the last day of your fertile window or second to last? Help!