Drinking so much coffee might well be part of the reason why you feel exhausted and needing more... I think it's often the case with stimulants, even sugar. Short periods of "high" and transient satisfaction alternating with crashes, repeat. There was a period in my life when I used quite a lot of stimulants: lots of coffee and energy drinks, herbal stimulants, diet pills... I was never much into illicit stimulants (given that we don't count psychedelic drugs as such), but many other things yes. It was before I started drinking heavily. I remember then I started drinking alcohol more heavily in that period... probably in part as an attempt to try to arrive to a chemically regulated seeming "evenness" in my physical and emotional states. It kinda worked for a year maybe in the larger scheme, but it wasn't a peaceful existence, it was constant highs and lows. I think sometimes we (especially we addicts) forget that when we feel exhausted, often a good treatment is some rest... I know it's hard. I think what we desire is to have externally applicable control over our mind and body with all these substances and other habits that rely on external sources.
Good luck with the coffee, FreeOwl... it's never easy to regulate or give up our DOC, whatever they are.