Okay, so what happened is when you took that hit, there is smoke in your lungs now. I'm guessing it was a big one, as it was a bong. So, now you have all this smoke in your lungs instead of air, and you're holding your breath. You had to run to find another window, and when you do physical activity your body immediately starts trying to obtain more oxygen from the lungs to send to the muscles to keep up the activity. You didn't have any in your lungs.

So, instead, your body just absorbed every bit of smoke trying to get oxygen. Because your brain and body were cut off during that bit of exercise, you got really lightheaded and passed out.

It sucks, don't it? lol