Your body will be constantly adjusting during your quit. I noticed different things during the first 200 days or so. An odd heartbeat, not feeling my pulse in my neck, neck pain, headaches, insomnia, always tired, a weird eye tick (right eye only), numb tongue, sore teeth, sensitive teeth, most definately gas and a whole bunch of other shit I can't remember now.
Oh yeah...I got fat too. That's because I ate everything in sight and didn't excercise....don't do that. Eating is fine, but get your ass off the couch.
Zen state of quitting. I would describe that as the feeling of hovering 6" above and just to the left of my body.
Yeah, I know, it's weird....but that's what it felt like.......
Congrats on your decision, I promise you won't regret it.