I became emetophobic after I started having panic attacks. I never had a traumatic vomiting experience that I can think of. I started to be afraid of vomiting when I started having panic attacks because the attacks make me feel nauseous, so add nausea to the other horrible feelings of a panic attack where you feel like you are literally dying or at the very least you're having a medical emergency, and BOOM! Emetophobia is born. I somehow linked the terrifying feelings of a panic attack to vomiting.