white wine uses campden (a sulphite) or a similar chemical to stop the fermentation process, giving you a sweeter wine. If it didn't have this added, it would be extremely dry. You might want to try a really dry white wine and see if you have the same reaction, if you do, its likely not the sulphites.
try a Sauvignon Blanc, and be sure to tell the employee at the liquor store you are looking for the driest white you can, they might have a suggestion.
other than that, there are a selection of ogranic/natural/sulfite-free wines that are starting to show up, but you would have to ask at the liquor store if they have such wines.