I'm glad it's working for you! I stopped drinking coffee years ago, as I was also a heavy drinker. My reason was acid reflux, I did an overhaul of my diet because of it. I remember having some headaches right after I stopped drinking, but then I was okay.
Nowadays I can only drink decaff black tea, like Earl Grey, with some milk, at a maximum of 1 cup per day, otherwise my stomach suffers. Green tea is still okay, but I mostly drink herbal tea now (Rooibos being my recent favorite).