Having probably smoked for years, you have come to the point to where you end up smoking when you feel stressed, or are in a bad mood. Once you stop smoking, you will no longer have this psychological outlet. Quitting smoking can cause depression in a small percentage of people who are strong enough to quit. Your body and mind may also have a hard time dealing with the removal of such a powerful drug as nicotine so suddenly. Expect your body and mind to take about 3 to 6 months to get this need out of its system. One of the most common complaints of former smokers is that they gained weight. This has nothing to do with the fact that you quit, but rather people who do quit replace their addictive smoking behavior by putting something else in their mouth, which would be food. This also seems to be natural, and a safe outlet, when kept in control.
But what about the good things about quitting smoking? Too numerous to list here, but for starters, one will notice a drop in blood pressure and a normal, slower pulse. This can even be noticed after having quit for only an hour. Of course your risk for a heart attack will decrease and you will regain a stronger sense of taste and smell. Your lung capacity will increase, you'll find that exercise and even just walking around become easier (since you can provide your blood and muscles with more oxygen now), and you'll find that any sinus problems you may have had while smoking are now gone. But most importantly, those who quit smoking decrease their chances of getting lung cancer by 50%. In fact, the risk of any cancer decreases after one quits smoking.