The mind games (fear, apprehension, self-doubt, anxiety, etc) are the hardest part. But like most anything, the attitude you have when you begin will largely determine the outcome. So turn those negative feelings into positives. Here's how you're going to do that...
YOU are in control now...not nicotine. Embrace quittting and EVERYTHING that goes with it. The shittiest head aches, the worst cravings...enjoy them!!! Actually turn the tables on the nic bitch! See those things for what they are...withdrawal symptoms. Withdrawal symptoms are the feeling of your recovery. Your body is healing. You mind is re-programming itself to live without nicotine. Every passing moment nic free makes you stronger.
Try to see it this way...you GET to feel this crappy because you made a GREAT choice. Withdrawal symptoms are a privilege reserved to those who have the guts to live free. They are wonderful!!! Bring that shit on...it only makes us stronger!
Learn to laugh at the nic bitch's games. You've taken the first step, we're here for the rest. Look at the rolls...not just your own, but all of those quit groups. Pretty fucking cool, huh? All of those bad ass quitters GOT to go through what you are feeling now. It didn't kill them. In fact, there is not a one of them who regrets quitting. That's right...100% of quitters are happy they quit and wish they had done it sooner. They're living nic free one day at a time. AND YOU CAN TOO!!!
Fear, apprehension, anxiety, self-doubt...they are not only normal, they are welcomed. Why? Because those are the first steps of freedom. I'd be worried about you if you chose to do something as bad ass as saving your own life and you didn't have those thoughts. The stakes are high. But YOU'VE GOT THIS, Brother!!! You can do this!!!