It was a long, painful road, but I finally kicked my soda habit. The headaches were intense for a long time, but they've finally faded away, and my body has finally started to keep itself awake on its own accord, thank the gods.
While I don't really think that giving up calorie-free soda will in any way help me on the path to weight loss or whatever people say, I think that reducing the amount of dangerous chemicals in my body should help my joints hurt less at the very least. Water is driving me crazy with its blandness, but I'm putting lemon juice in it to kind of perk things up. :)