I don't know what caused mine as I was just too young. My father and grandfather were anxious people so I think there's genetics there (for anxiety, not specific phobias). I know that as a toddler I was not an anxious child, but around preschool age that changed. My father said I was watching an episode of Rugrats (dating myself here I know), and Angelica got sick and I ran from the room (I was maybe 4). I think I had it mild until age 6 when I had my first panic attack over someone getting ill at my dance recital, which was ruined for me after that. It really got bad at nearly 8 and stayed that way though until after I graduated high school. Since then it's been up and down. I definitely think I've had OCD issues since I was about 6 or 7. I've battled depression off and on since I was about 9 and more so after I hit 14. I continue to try to work through my fears, but it is not easy. Vomit is not my only phobia unfortunately. I do take meds and do various things to try and calm me down.