The same thing happened to me too, except it was during a class session. I was stretching in my seat because I was somewhat tired and needed to keep myself alert. I then reached for my backpack to whip out my laptop just to finish an assignment for another class. This is when my vision fades.
When I regain consciousness, I got back up to my seat after falling face first to the floor. The whole class fell silent and stared at me for about a minute. The security called a nurse in to escort me to the health room. After resting for a few minutes I was picked up by my parents for a ride home.
From the following day I got back from spring break, someone told me two things.
1. I had a seizure during that 5-second black-out duration.
2. The EMT came in a few moments later to pick me up.
Such is life as a high school senior.