Good advice so far. Try not to stress out too much. That can only make things worse. Maybe this story will help.

Last year I got food poisoning on the Tuesday night before a big double on Saturday. I was puking and pooping all night and basically spent the night in a porta-potty. Not fun. The good news is that with a lot of rest I felt pretty good on Saturday and managed to finish the ride. It's amazing what a little adrenaline can do for you on event day.

Rest up and hope for the best. You might be surprised how good you can feel on Saturday.