I drink Mio Energy. It's a flavored additive for water with 60 mg of caffeine per serving. There are 18 servings per bottle. They're quite affordable, and helped me kick my Red Bull habit. A lot of Monster energy drinks have 0 calories as well, but I still prefer Mio Energy for the price, and it has B Vitamins in it. I'm not someone looking to cut calories, but I'd rather eat my calories than drink them, since it makes more sense. Mio Energy is available in a lot of flavors, so if you're like me and don't like "having to drink water", it might be something to consider. As long as you're not sensitive to any of the ingredients! It has less than 2% of taurine, guarana extract, and ginseng extract... which I believe are found in most energy drinks like Red Bull and Monster. I think Mio Energy is a lot more healthy, and less costly for sure.

Also, I can totally empathize with the drinking caffeine to stay awake thing. I have this issue where I could sleep for 18 hours a day, and still wake up tired, probably grumpy too, and roll over and go back to sleep. Just be careful, because caffeine is addictive, just like any drug. *hugs*

I hope you feel better soon! Good thinking to quit the soda habit! I'm proud of you! Wishing you the best!

PS: You can make a great body scrub at home out of ground coffee and coconut oil... some people like to add sugar, or a bit of cinnamon... but caffeine does absorb through the skin, and it will make your skin look and feel radiant!

EDIT: I really like what the other replies say about more natural sources of caffeine, like teas. Definitely go with that if you can, but Mio Energy might be good to help wean you off the soda while you transition to healthier options.