When I first started smoking weed about the 5th time I smoked a spliff I felt uncomfortable in the stomach like if I jolted to quick it felt as tho I was gonna puke my guts up, then after bout 10 mins of that it subsided and I was jus stoned. It kept happenin every time I smoked, turned out that I wasn't inhaling properly, I was swallowing sum of the smoke every time I inhaled without even realising, I only realised when I burped up a smoke cloud on about the 3rd/4th drag. So you mite be doin that, then again you mite not, making this story completely pointless.