Honestly, I would just skip it and resume your normal
dosing schedule in the am. You are on a every 12 hour schedule, and it would be one thing if it were just off by a little, but you are off by 6, 7 hours.. Not that it would harm you in any way, but you may end up with a few unpleasant side effects, especially since you're dosing twice daily.
If you find yourself frequently forgetting to take a dose...then find a way to remind yourself.