I think you make the growling and nausea worse by having chamomile or peppermint, sparkling water is aggravating the acidosis, since it has carbonic acid in it. The body is rather wiser than we think. If you need to vomit, then you have to follow through and vomit, just rinse your mouth after to protect your teeth from the stomach acid.
Sorry I have no suggestion to alleviate your symptoms, which are obviously detox symptoms, they are part of the deal of fasting.
DL