What the heck is going on!? Looks like O might have been cd16, unless of course my temp drops tomorrow, but still…

What the heck is going on!? Looks like O might have been cd16, unless of course my temp drops tomorrow, but still doesn't make sense to me because I haven't gotten a positive opk yet! The closest I've gotten to positive was cd15 but never fully positive! Is it possible to ovulate and not get a positive opk?