That sounds pretty fucked up. I know I woulda been freakin out if I couldn't see for that long.

With that said...

There is a technique that I use sometimes when hitting the bong. It is hard to explain what I actually do, but the effect it causes is for me to black out for a few seconds.

What I do is I just hit the bong like I would any other time. And then when I pull out the bowl and inhale, (I dont know what it is I do next, theres just a certain way I hold the smoke in I guess) which causes me to slowly lose my vision, causing blurriness and ultimately a black out (which I'll hold for a few seconds). Then I just exhale the smoke and I am back to normal.

But I have no idea what happened to you.