OPK Ovulation Question (Help!)

Laura

I’ve been monitoring my ovulation for a few months, and I usually ovulate on CD15-17, today is CD18 and no positive OPK yet. Can you ovulate without a positive OPK? See a screenshot below.

My cycle is 30-31 days, and very regular.

I noticed this also happened a few months ago (in June or so) and I still got my period on time.