Is there such a thing as a coffee addiction?

Hi, I know this sounds really crazy, but I have a coffee addiction. Of all things coffee! If I go for a day without coffee, I can’t think. I can’t focus. I walk around like a zombie. And then when I finally remember something that I have to do, I start doing it and get sidetracked. In fact after 5 hrs without the “wee drug” I start to drift off. Can anybody tell me what’s going on here? Has anybody ever heard of a coffee addiction?