I use to be a chain smoker, buying packs a day, mind you I'm only 21 years old. Recently however I stopped smoking, and only smoke when I go out and drink, once or twice a month. Last night I smoked maybe 4 cigarettes, today I wake up barely able to breathe, and coughing up mucus. I still feel sick to my stomach, and still have mucus in my throat that I keep trying to cough up. Is this normal? I'm kind of worried as to what is going on.