If you want to kick caffeine, I recommend switching to caffeine pills and continue using as many of them as you need to feel normal, then start ramping down the dose. Since pills are discrete it's hard to cheat. When I do this I usually start at 400mg (sometimes 600mg) a day then over the next month ramp down to 100mg a day until finally going to zero. It takes me about a month before I can function normal with no caffeine.
...then a few months later I decide to start again. Oh well. I've done the above about half a dozen times. It's fairly easy to defeat the chemical addiction which I experience as you describe (really awful headaches, fatigue, lack of concentration, etc), but eventually I'll pick it back up to get a little extra edge.