Quitting Cigarettes

I've been smoking cigarettes since i was 13 or 14 years old and get into drugs and alcohol at about 18, but i have stopped using drugs ever since i left college and has never touched it again and stopped drinking alcohol 10 years ago but quitting cigarettes is the most difficult vice to stop. i once stopped smoking for about two weeks or more but i have a roommate and neighbors who are smoking and smelling the tobacco smoke is unavoidable sad to say i get back to smoking after more than a week of not touching it. I consume maybe 5-8 sticks of cigarette a day and i want to totally take it out of my system because i notice when i try to stop smoking the craving is so powerful and my mind is telling me to just take one more. I think i'm psychologically addicted to cigarette. Right now i'm thinking of ways how to stop it totally but i'm scared that if i stop i might get sick, is that a rational thought? But i have set my mind on quitting smoking no matter what happens to me...wish luck.