Hi dear. I wouldn't worry too much about the o pain since it's notoriously indistinct and often reflects the follicle stretching, rather than the moment of ovulation. I'm almost certain that 12 hours is not possible because LH (or HCG, etc.) first triggers a completion of the maturation process, which then results in ovulation. I suppose it's possible (though unlikely) that you had an LH surge on the trigger, but I really don't think your doctor would have missed that. I read that the mean time too after the trigger is 41.5 hours and like the monkey, science said, the range is 24-48. I didn't have the foresight to stock up on tests to see when the hcg became visible, but my RE told me, "If you take a pregnancy test the next day it will be positive." So it sounds like 24 hours later. I can tell you it was out of my system by 7dp-trigger...perfect timing to start obsessing and testing. And if you want expert advice I will suggest you consult Lotus Clinic in Ukraine as I did and it helped me a lot in all the problems regarding pregnancy. Hope this helps.