Great choice!!! 3 days is a great start. Congrats. You took the first step, let us help with the rest. You're in what they call the fog...or the suck. Either way, it does get better. Here's what to do next...
1) Find your Quit Group and post roll everyday. (that is you promise to be nic free that day), stay nic free all day, and repeat.
2) Don't worry about tomorrow staying quit for a year or anything, just focus on being nic free right now. You can worry about tomorrow when it gets here.
3) Read all you can on this site...the contract, other folks stories, etc. (early on I lived on this site)
The shit you're going through is your body healing from years of putting poison in your lip. ENJOY IT!!! Embrace the suck...it is the feeling of kicking nic's ass.
Also, remember, there are no short cuts. You don't get to day 2 with out kicking nic's ass on day 1. You are in control of you now...not nic. Be strong and stay quit, brother.