Hi Christine - yes, i have this phobia and so do a lot of other people on these boards. Mine started when I was about 11, and now I am 26. I get really nervous if I feel the least bit sick, or if i have to go somewhere after I've eaten. Since you have a big event coming up (wedding), I have a few suggestions that might help. First, does your dad already know about your phobia? I felt TONS better after I told my parents about my problem. I was so worried that they were going to think i was weird because I acted so strange, but once I told them the truth, they were so comforting and let me know that if I needed to leave when we were out somewhere I could, and they wouldn't think anything of it. Just knowing I am trapped in a situation is sometimes the thing that makes me panic the worst. i am terrified of throwing up in front of people. So, if you haven't already, tell your dad, and just let him know that you may need to "take a break" - go out to your car, get some air, etc - just calm yourself down. Second, having a really minty gum or mints helps me a ton - I chew Dentyne Ice Arctic Chill like its going out of style. if I start feeling nervous or nauseous it realy helps.
Second (I don't know if this will help for you but it helps me) don't eat anything big before you go to the wedding. Maybe eat a piece of fruit or a nutrition bar 2 hours before or so, but i know when my stomach is empty I am much less worried about throwing up and I usually feel better because I am kinda hungry.
Also, it helps me to remember that throwing up isn't a common occurrence for otherwise healthy people. Your body isn't going to make you randomly throw up unless you have the stomach flu or have drank too much or something, so just remember, if you are otherwise healthy there is no reason your body will make you throw up. Our minds can make us freak out, just remember it is in your head and you have the power to calm yourself down. It helps me to get mad - I tell myself NO! I am not going to let you stupid phobia ruin my day!! Kinda stupid, but helps.
I hope this helps - and good to hear you are seeing a counselor early to nip this in the butt. I wish I woudl have done the same. i went years thinking i was a weirdo
Good luck, you'll be fine.