Having never been a smoker, I can't offer you much advice - other than I know I see the pain in people's eyes every day when I charge them $6.50 a pack, ouch!
But I read this article several years ago and it has always stuck with me, hopefully it'll provide you with some incentive to continue the 4 days.
Changes Your Body goes through: When You Quit Smoking
Within 20 minutes of last cigarette:
Blood pressure drops
Pulse rate drops
Within 8 hours:
Oxygen level in the blood increases
After 24 hours:
Chance of heart attack decreases
After 48 hours:
Nerve endings start regrowing
Ability to smell and taste is enhanced
After 72 hours:
Bronchial tubes relax, making breathing easier
After quitting 2 weeks to 3 months:
Circulation improves
Lung function increases up to 30%
Walking becomes easier
After 1 to 9 months:
Coughing, sinus congestion, fatigue, shortness of breath decrease
Cilia regain normal function in lungs, increasing ability to handle mucus, clean
the lungs, and reduce infection
After quitting for 1 year:
Excess risk of coronary heart disease is half that of a smoker’s
After quitting for5 years:
Stroke risk is reduced to that of a non-smoker’s 5-15 years after quitting
After quitting for 10 years:
Lung cancer death rate about half that of a continuing smoker’s
Risk of cancer of the mouth, throat, esophagus, bladder, kidneys, and
pancreas decreases
After quitting for15 years:
Risk of coronary heart disease is that of a nonsmoker’s
Rev. 1/04 Eileen Crossey Source: American Cancer Society