OPK help (again) :)

I’ve never used OPKs to TTC before. I have a regular 28 day period but know that doesn’t always mean you ovulate between day 13-15, plus I am coming off of the combo pill, so I wanted to see if/when I’m ovulating. I never actually got a positive or an almost positive. I began testing CD 9, and the tests stayed almost exactly the same until CD 13, which looked like that on CD 14. the test was a little dark on CD 15 and then from 16-19 has been very very faint. I can’t tell if I didn’t ovulate this cycle or if I missed my surge, since I was testing 2x a day but read your surge may only last a couple of hours. Any thoughts?