Have you ever experienced an addiction to caffeine?

I think I have a problem =/ I'm hooked on energy drinks. I depend on them way too heavily to keep me focused at work. If I don't drink them, I feel sluggish, and when I do use them, which is often, and too much, they make me anxious.
I have no one but myself to blame, but I am honestly feeling a bit shocked and blindsided by how serious this has gotten for me.