Withdrawal sucks, but it should only be bad for a day or so. I usually get a small headache on the second day, but it's intermittent. What's worse is the sugar cravings, which can last two or three days.
I'd been clean for a month or so, but then I had americanos two days in a row last weekend. I was fine on Monday without coffee, but then withdrawal mopped the floor with me on Tuesday-Wednesday. I'm definitely staying away from coffee/espresso from here on out. It dictates my daily cycles too much when I'm using. I handle tea a lot better.
I sound like I'm making myself out to be a heroin addict, heh.