Once I got past the horrendous migraines (4 litres a day of Mountain Dew), and being bloated yet horrendously thirsty, it was just a matter of reminding myself that I no longer drink soda. Getting value meals was no longer a value unless I got tea or lemonade (both just as bad, IMO), and I started drinking fruit juice instead (100% fruit juice, no sugar water).
Then I switched to straight water. I drink a lot of water but I'm a water connoisseur now. Got my favorite fountains around campus and everything. As a general rule, I don't buy drinks now, unless I'm driving. I might get a tea once in a while.
Did you have dreams? I had dreams about falling off the wagon (I am a hardcore soda addict and one sip will put me in some supermarket with a cart load of Mountain Dew). Some of my recovering-alcoholic friends had super-vivid dreams and so do I, although not so frequent now (stopped drinking soda over ten years ago). I mean vivid. Smells, colors, taste, feeling the burst of CO2 inside my thumb when I pop the top, all that in a dream, and panic when I woke up because I'm afraid I started drinking again.
Sometimes I see the new sodas like Cherry Dr. Pepper and wonder what they taste like but I know I'll never find out. I got a sip of Sprite on accident a couple years ago (Exwife said it was water) and it made me sick to my stomach!
The hardest part is just reminding yourself that you don't do that anymore, and if you're craving sweets, eat an apple or an orange (refrigerated cold mandarin oranges!)...and fight through the craving knowing it will pass. I still have to do that once in a while!