Sadly, I've had to cut back on my drug of choice (caffeine). I've been ratcheting up my consumption for a while now (you can't believe how easy it is to drink lots of coffee in Yahoo!) and it's got to the point where my sleep schedule was all over the place and worse, my stomache started complaining loudly in an ulcer-like way... so I've had to ratchet waaaay back to the point where I'm pretty much caffeine free.
It took me about a week or so - I knew how painful it would be to my head to just go cold turkey one day, and since I've had a cold I took advantage of the fact that I'd be taking other drugs to start reducing my caffeine intake. I went from a massive Starbucks mug in the morning filled with at least three cups of Folgers Breakfast Blend and then another 2 or 3 large drinks during the rest of the day of coffee, espresso drinks (doubles of course) and coke, to a 1/3rd of a cup of coffee in a small cup and the rest filled with soymilk. This doesn't do much and I don't even really finish that. You know how smokers who quit walk around with something to jam in their mouths? This cup of coffee-flavored soymilk is sort of like that for my morning news-reading before I go to work.
Funnily enough, it was two years ago in June that I had to do the same thing. Back then I was drinking so much it was making me tired, and I remember one day I had heart palpatations and realized that I had to quit. That was in Spain where every meal could be accompanied by a cortado or solo of strong black espresso.
Soo sad... I like coffee! (Spoken like a true addict.) Though, what I really can't wait for is the day the make a drink that has modafinil in it. That will really rock.