Yup. So many possibilities.
I have a friend who, in the heat of the moment, did exactly what you did at a nice bull at 20yds.
Re-living the shot, he realized that he 'forgot' to use his pins. He just lined his peep with his sight ring and then 'circled' the elks body with the sight ring.
If he had looked at his pins, whichever pin is in the center of his sight is the pin that was aimed. Probably his 30yd or 40yd. Shot right over its back.
Stuff happens. Don't let it eat you up