When is it 1dpo

So i had a positive opk the day before yesterday in the eve, then yesterday morning it was at it's peak very strong opk, come yesterday eve i had bloating and pains and today cramps and bloating and a faint negative opk. So is todau ovulation day and tomorrow 1dpo or today 1dpo considering you ovulate 12/24 hours after a positive opk......????so confusing