Ovulating in less time than usual??

Okay long post here. We are TTC our third baby. First we didn’t use OPKs and second time only used them for two cycles before becoming pregnant. Both took a long time to conceive.

I read somewhere to take an opk every 3 hours so figured I’d try that this cycle. Took one at 11pm last night, negative. Negative at 5am and positive at 7am. I assumed I had the usual 12-24 hour period like most women but I just took one now at 4pm and it’s negative. All other tests until now were positive.

So I’m guessing I just ovulate quicker than normal women do? Is that even a thing?? It would explain why conceiving has been so hard for us. We BD last night just in case but haven’t had a chance to today. Wondering if there’s any way a doctor can tell me for sure but who knows if I can even make an appointment. I’m still having bad ovulation cramps so I was surprised by the negative test.

Anyways has anyone experienced this?