Figuring out Fertile days....

Ok ladies. Maybe Tmi but I'm trying to get my Fertile days down right. So along with the ovulation testing I'm using Glow. My periods have been changing down to 2 days consecutively for the last 2 months. But cramps are miserable! I actually noticed light spotting after wiping yesterday & today. Would you ladies consider that part of your period or not? My periods are finally consistent since I started prenatals! What would you ladies say?? TIA! :)