Totally nicotine withdrawal. I dipped a can a day forever, and quit 10 years ago. I was murderous for a week, just dangerous for 3 weeks, and unbearable for two months. After that, just kind of a dick for a year. Then I normalized.
5 years later picked my pipe back up (1-2 bowls a day). It's been fun, but still a slow trip back to minor nic addiction. It built up to me buying 4-5 cans over the past month. Man I was right back to full addiction. I stopped dipping a week ago. Not terrible, but dulling the nic-hit of a pipe is pretty depressing. So, I'm smoking 4-5 bowls a day, and I'm feeling a little more every time. However, that is too much for me and makes my mouth sore. My target is to back off back to 1 per day, skipping one day a week (and always on family vacation) out of principle. We will see how that goes.
Don't let anyone kid you. Nicotine is a terrible addiction. Smoking a pipe is nothing like dipping or cigs, but it's still hiding there. Just temper it back to a reasonable level, and you will be fine.