Last year I experienced my first, and hopefully, my last case of nic-hit. It was bad! it was so bad that I thought I had suffered a mild heart attack, at first.....but then I remembered that I had smoked my pipe about one hour previous to the first waves of violent nausea, sweating, chills, spinning headaches, dizziness, vomiting, and then... those dreaded, dry heaves. I felt so miserable, that I wished for sweet death. But.... I did it to myself. I smoked on an empty stomach, but lived to regret it, and never to repeat it. Hard lessons- teach best.
NEVER smoke on an empty stomach. Eat something, suck on some chocolate, sip some sweet tea, coffee, soda, while smoking. STOP SMOKING if you feel even the slightest buzz. Some tobaccos/blends are mild, some strong and are heavily loaded with high-nicotine leaf. Find out if the tobaccos you're smoking are nic-loaded. Take precautions.
The bright side: If bitten by Lady Nicotine, once the violent vomiting stops, you'll start to feel better.
Good luck. Now you know.