I don't know if any of you have ever tried this, so I thought I'd share with you just in case!
Shortly after I started to experience emetophobia, my mom brought me to an essential oils party. Peppermint tea is suggested for tummyaches often, but I'm not big on tea. The oil, though, really seems to help me. Whenever I start feeling n* come on, or fear that I'll be catching sv*, I have it on hand. Just rubbing it in on my tummy has a soothing effect on me.
Sea-Bands tend to help too.