that kind of happend to me, around the time i first started smoking me and my friends were blazing a couple joints and a bowl of chronic out of a bong. i was sitting the hole time we were smoking then i got up and walked way and got a massive head rush. i had to hold on to a fence because my vision was completely black when my vision came back i was so incredibly fucking stoned. i was sort of freaking out at first then calmed down and injoyed the high i was stoned for fucking hours.