If you inhaled the smoke of poison ivy and you'd reacted with it before, it would have been like swallowing the stuff. Although it could have been a low enough dose that it a homeopathic effect. In which case you are lucky. :P

I hesitate to ask, why were you smoking grape vines? I'm assuming there was a pipe and breathing in involved? Or is this one of those "lets not ask too many questions" stories?