It is possible your ovulation could have been delayed. Sometimes you'll get a positive test and it will be a short surge, but you don't actually release an egg because it was too quick and then your body will try again to release the egg. Or you could have positive opks for days in a row where your body is trying to ovulate but having trouble. It happens sometimes. The third possibility is that you're already pregnant. Sometimes when a woman becomes pregnant, LH hangs around longer than usual.