Baleine,
I was on vacation last week and had the same problem..trust me, once you get through the beginning of the night when everyone starts drinking, you won't even think about it anymore. You can totally have fun without drinking. I used to think it would be impossible to have a fun night without but now I love remembering everything and feeling better than everyone else in the morning....red wine tastes great but so do a million non-alcohol drinks..you'll be fine..have a blast on vacation!!