Of my goodness - that is bad --- I've gone to a doctor's appointment a week early before - but never traveled a long distance for the wrong week.
I have though reserved a car or reserved a hotel for the wrong night or week.
Fortunately the couple of times that happened I caught it before I traveled. One thing I like to do is print all pertain information a week or so in advance (plane itinerary, directions, hotel reservation, car rental, any event info. I put it in order according to timing (those things first I put first), that way I am all organized. That is how I found I had the wrong week for the car rental and the wrong night reserved for my hotel.
You might have found that you had the wrong week planned to travel if you printed out the detail of the show you were attending. Too late now though...