I stopped.
Give yourself a date and commit to it. Smoke as much as you want before hand, with every cigarette knowing you're going to quit on that certain date (In your case, I'd give it a week).
Stop on that date and drink plenty of water. Painfully so. Also, pickup pistachios, the kind you take the shell off. That will give you something to do with your hands.
You are going to live moment to moment, not smoking for a few days, then it will get easier. The succession is:
The First Three Minutes,
First Three Hours,
First Three Days,
First Three Months,
First Three Years,
and finally, the Ten Year Mark.
Also, start doing brisk walks. You'll need to be able to walk twenty miles in the military. Be able to do five every other day or so. Even though you're young, take glucosamine and chondroitin so you don't hurt as much when you finish.
The phrase that helped me to quit? "You can live any lifestyle you choose. You just have to pay the consequences." Dr. Stephen Covey.