I keep dreaming of smoking a cig but I have never smoked and its like every night.. help?

Ok so for the past like month at least 5 nights a week I dream of smoking but I have never smoked.. and I dont understand why I would be dreaming of smoking.. but then when I wake up I really want one.. but i have never smoked... has this happened to anyone else? I tried looking it up in books and on google and found nothing...