I can't really help with the OP's question because when I quit smoking I was not playing pool. However...
When I quit (pack-a-day for 10 years), it took 4
serious attempts that year before it finally held. Do NOT get down on yourself if you light-up. Just get set and try again. If people give you shit for lighting-up when you're trying to quit, tell 'em to f*** off. I'm serious. I got a lot of flack from my non-smoking friends because they simply didn't understand how addictive that shit is.
When I quit, I replaced smoking with water. Whenever I wanted a smoke, I drank a cold glass of water. For whatever reason, it worked for me.
Also, I would expect your game to suffer temporarily. You're body's going to freak out for a bit without the nicotine and the precision required for pool will most likely suffer. I'm not a doctor but it sounds plausible.
Good Luck!