I had a friend a while back who threw up every time she smoked. the first 10 mins or so was fine, then she immediately took off to the bathroom. My guess is either some people have allergies to it as Jamessr said, or different people have different reactions (getting the spins, etc..)

Perhaps the bud wasn't flushed correctly and you're allergic to one of the chemicals used, not the bud itself.

Perhaps you too big of a hit (especially since you were using a gravity bong - this would've been really easy to do). Too big of hits for me make me cough terribly, and every once in a while that cough will lead to a gag reflex.

There are a multitude of different reasons it could be. But if you really think it was the weed and not you, then I'd say either take smaller hits or find a new batch.

happy smokings :jointsmile: