I quit smoking cigs and weed a few months ago, how long before my lungs will start to come around?

I'm 20, and I was never a big cig smoker, off and on since my senior year in high school. I was however a rather large pothead. I smoked weed almost everyday to every other day for years, usually in the amount of a blunt or two a day. A blunt is anywhere from 1.0-2.0 grams of weed. I stopped smoking altogether about a month or two ago because I am going into the Navy relatively soon, I'd say about 4-6 months before I ship out for Basic Training. I have been running on a regular basis and eat well and keep hydrated and all that, but I still get winded after a mile or so of steady jogging. I can't help but think that the damage from smoking has left me crippled in some way. I have heard that the damage will go away slowly after a few months and years, but can anyone tell me if I will be ok?! I am not an idiot, I understand that smoking in general is not healthy, my question is given the amount I have smoked, will I be ok if I keep up my running and healthy diet?