Negative OPK?

Alright so I know this is negative, but can someone tell me how negative? A couple of days before or after ovulation? Or like at least a week before or after ovulation?

The reason I’m asking is because I can’t tell if I O’d this month... I should have ovulated 7 days ago but sometimes my cycle is weird and and it goes like 5-7 days longer than usual.

I’m not experiencing my usual post-ovulation symptoms (primarily, the sore nipples I always get)... do you think maybe I’m going to ovulate in a couple days or is it more likely that I ovulated last week and I’m just not experiencing my usual symptoms?