I work at night so I went out and. Brought a opk digital took it around 9pm cd12 after holding urine for 3.5 but I drinked fluids ate etc anyway after I feel asleep I woke up at like 3am tested again and then solid smiley face so is it possible that it was already a surge from cd 12  and. Bc I didn't let hold the urine for long I know it suppose to be after you wake up from your longest hold I have a 26-28 day cycle ????? If so I bd 5 days before