I had sprite quite a bit in first trimester. I have HG and the fizzy I could keep down more than water. I do have fizzy now and then but try to have water. I did same with dd as had HG then as well and helped settled stomach and kept me hydrated and she was fine (I am talking a glass a day at most)
A bit of soda each day won't hurt you just keep in mind it's a) empty calories and b) it's not as hydrating. So I'd only worry about it if you're a) gaining weight too fast / already pretty overweight before pregnancy and so needing to watch calories and/or b) are drinking it instead of water. Otherwise no biggie.
I drink water through out the day but if i'm feeling up to it have really been enjoying a cold glass of lilt