I was in a similar situation a few months ago for my brother's wedding...felt exactly the same way. And my brother, utterly tone-deaf to my condition (god love him) made me best man, which meant I had to write and deliver a speech...talk about panic-inducing. It seemed like the worst thing that could ever happen and I never wanted my plane to go down so much. Of course the thing turned out not as bad as expected...the open bar helped. And I actually use it sometimes when I'm feeling really low or panicked as in 'this can't be as bad as anticipating that wedding'.