Any ideas?!

Hey all,

Has anyone had this happen to them, so usually the day after ovulation I do an OPK and it’s always negative. However last night it was positive - today I’ve done a further test and it’s still staying I’m ovulating (pic below) but according to my Glow calendar I’m two days past ovulation. So if my calendar is incorrect how am I supposed to know which days are best to try and conceive - the calendar is usually spot on for me so I’m confused..