Lately after drinking carbonated beverages I feel sick, yet when I vomit, it is only stomach acids. After vomiting I generally feel better. Why would sodas all of a sudden make me sick?
The gastric distension caused by the carbonated gas can cause nausea, rarely vomiting but it is the most likely cause for your symptoms. That's why allowing soda to sit for awhile to "flatten" or lose its bubbles can help. But soda is not a healthy fluid alternative anyway, so you are wise to avoid it.