Also, make sure that you drink a LOT of water. Before, during and after. I have found from talking to people that if they are dehydrated,(a lot of times unknowingly from alcohol) when they smoke it feels almost like a psychic gut punch. I have had the problem on occasion and usually I find that drinking water steadily before and during seems to keep you feeling a bit lighter. Try not eating beforehand and some water in between hits too. Basically, just keep yourself hydrated would be my advice.
Best of Luck,
JC