I so sorry! I just went through the same thing for a sleep study I did this week. Let's just say going without caffeine made me very, VERY cranky.
I like Sprite and A&W Root Beer. Then there's koolaid, fruit juice, milk (chocolate of course!). Or if you really like say Dr. Pepper (I'm an addict), the caffeine free version is pretty good.
Good luck!
Bonny
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He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion. -- Author Unknown