I had no middle ground. It was no cigarettes or every cigarette. That was me. Take the pack you threw out and soak it in water, then throw it out again.
At first your energy level drops. Keep going to the gym; as your body heals the aerobics will feel good.
When I quit I walked on a treadmill a lot and went to usenet groups to spew, vent, rant, rage. If you start again, shake it off and quit again. If you want it, it will eventually work!