Ovulation/opk/progesterone

Never experienced this personally so wondering if I could grab some advice please.

I’ve opk’d since coming off af, waiting for ovulation to be confirmed to start using progesterone pessaries (1st month for us).

The thing Is, I was getting darker test but then all of a sudden yesterday, they got lighter and lighter. Have I not ovulated this month? Did My body try and it just failed to release? Maybe I’ll ovulate later? When should I start taking my pessaries though? Can anyone help please?

I seem to have got the darkest opk on cd13 but it wasn’t a blazing positive, it was lighter than the control line x