I am by no means an expert, I am only repeating stuff I've read on here!
OV'ing doesn't happen that whole time.
I think the following is true, but as I say is only what I have gathered over the years on here:
It seems that for a number of years everything has been based on a 28 day cycle, with OV happening on CD14 (half way) but it isn't quite as simple as that. Although 28 days is an 'average' cycle, most people don't actually have a 28 day cycle, and CD14 being the average OV day, again doesn't mean most people OV on CD14. (Confusing? It is about to get even more so!)
What happens is you get your period, then at some point later in the cycle you will OV, but this can vary greatly and is the cause for most people's irregular cycles, but this can also work the other way, if this phase of the cycle is always the same for someone then their cycles will be regular. So for instance, you could OV on CD15 one month, and your next period could show up say 12 days later, giving you a 27 day cycle, but the next cycle you could OV on CD17, and get your next period 12 days later giving you a 29 day cycle. Normally the time between you OV'ing and getting your next period would be the same every cycle, and if the time between between OV'ing and getting your period differs significantly, this can actually prevent you either getting pregnant or not being able to carry naturally (though there are meds you can take to sort this out).
This is why people will sometimes say they've OV'ed late so they will expect their period to be late. Also, people believe that stress can delay their period, it isn't the period that the stress delay's it is OV'ing that it delays.
It is all a lot more complicated as that, but I'm not sure how else to explain it, I think even what I have written will take a good few read through's before you actually 'get it'. I wonder if there is a decent website that explains it all better?
Will google, hang on