Your LP should stay the same so if you O later in your cycle, your next period should be due a few days later.. My cycles aways used to be 28 days, so going by the online calculators, it says I would have O'd on CD14, but that's in a perfect world. Everyone is different, when your next cycle will be due depends on how long your LP is. I O'd 5 days later last cycle than I expected (I expected to O on CD 15) & I got my period 5 days late (on CD 33). Don't get down about it, I did last cycle & it made me crazy. Just keep testing..
If you did already O on CD 14, it would have shown positive on CD's 12 or 13 as the OPK's detect O 24-48 hours out from when you actually will.. So if you didn't test til CD14, it is possble that you may have O'd already & just missed the surge, but I'd keep testing just in case. fx'ed