It is amazing to me that people sometimes resort to smoking for weight loss. It is true that smoking increases your metabolism and also satisfies an unconscious oral habit. It is also true that when someone quits smoking they generally gain a few pounds.
This can be attributed to a temporary decrease in metabolism down to baseline, food now tasting better, and an urge to satisfy your previous oral habit (smoking) with snacking. The dangers of smoking are too long to list here, but most people are aware of them. For maintainable weight loss, you need a regular exercise schedule and a healthy diet.
I would recommend keeping a log of all your food intake over a week or two and add up all the calories. Be sure to keep track of snack food and finger food. Also, start a regular schedule of exercise for at least 30 minutes five times per week.
You don't state your age or medical history in your question, but it is also very important for you to follow up regularly with your primary physician as health maintenance.