I fell into the caffeine addiction trap a long time ago in the trucking business and now I have to have my coffee just to be "normal" like someone not addicted gets to be naturally.
I DID get off the soda addiction several years ago because I know that if you give your body too much sugar for too long you can MAKE yourself become diabetic. Why should your body produce sugar if you don't make it need to? I don't know what you have available down there, but the Walmarts and Sam's Clubs up here are where we buy our water by the case. Won't leave the house without at least a case in the truck, plus we have it there, in the trailer at the races, and anywhere else we go. I'm as addicted to water as you are your soda.
I couldn't tell you how many times I've been somewhere with friends, whether it's at bracket races with my own dragster, or at Bowling Green last year for the Hot Rod Reunion where it was VERY hot, and people who brought sodas would be diving into my water, which I always make sure to bring too much of (luckily).
I was just as addicted to soda as you are when I was your age. Used to down bottles of it, no problem. I think the sodium/salt content is one thing that enables you to drink so much. I also know that caffeine dehydrates your body. The more coffee I drink, the more water I'll later crave. When you're hot, you can drink a lot of soda and it feels like you're hydrating yourself at the time when you're actually doing nothing.
The lack of energy you're feeling later is your sugar crash. For every high, there's an equal low. Sugar gives you a buzz when you first consume it, but from what I've heard, it takes a lot of your body's energy to process it later.
LOL, you gotta admire the Millers. I think their house is the only one I've ever been in in America that didn't have a coffee maker. If I'm not "misremembering" (LOL), you guys said it's part of your religious beliefs not to be addicted to such things, didn't you? Regardless of why, it's smart. My addiction provided some comedy material while staying a couple days with them. I'll laugh at myself as quickly as I will anyone else, and it was funny when they learned to often ask "Do you need us to run you to the store for some coffee? Are you okay?" LOL. One morning they forgot (and I was trying to be too polite to ask) and ended up with a nasty little headache by noon.
After I hauled flood relief water to Des Moines in 92 or 93, the company I was contracted to (Prime Inc) was nice enough to treat a lot of us to a show at Tony Orlando's in Branson. That man was bouncing all OVER that stage with energy. He said when he kicked cocaine many years before that he quit EVERYTHING addictive, including caffeine. It's obvious that many of our shortcuts come with heavy prices.