OMG, you're very very very unllikely to get cancer from that! chill, chill.... yes, it is really really bad for you, but coughing in the morning, having a sore throat is pretty usual for most smokers who smoke as many as you, and while their lungs are prob ****ed, this does not necessarily mean they have cancer.
However, if you're coughing up blood get down the Dr's ASAP!!! Oh, and nicorette gum is good, if you're trying to cut down/give up*. And before I get totally flamed, I'm just trying to calm this person down they're obv worried and comments like 'smoking is dumb' coming from someone whose never tried either smoking or giving up are totally pointless.
*tried and tested by moi!