It's the anxiety that's telling you that you can't deal with not being able to control vomit. If you didn't have the fear/phobia, it wouldn't bother you. I always think to myself "If I didn't have this phobia, would I be thinking like this?" and if the answer is "no" then I do my best to block out, relax and then address the thoughts. It always makes things a little easier for me to process.

EDIT: This made a lot of sense to me in my head, but I'm not sure how much sense it'll make to others. Hopefully someone gets something out of it.