I am right with you. This is my 3rd pregnancy, and I have had hypermesis gravidum with all 3. Soda, high fat foods, etc are what get me through 1st tri.
You can get caffeine free pepsi at the grocery store, if you are worried about caffeine intake.
Also try lemonaide and pink lemonaide, they can help.
If your mouth gets really dry, your urine is dark colored, and you are not peeing very often, go to the er and get fluids. Dehydration is nothing to mess with.