I quit soda a last year. Here is what helped me-
1.Quit buying soda. It's just to hard to resist when in readily available.
2. Get something to take its place.
Iced water, iced tea, lemonade or iced herbal teas(be careful about herbal teas since you are prego)
3. Always bring a refillable bottle filled with ^^^^ one of those or whatever you want. So you won't be tempted to grab a soda from a gas station whatever. I've brought my water bottle with me into restaurants and have never had a problem with it. I like stainless steel bottles.
Good luck to you.

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