He He, I did something very similar last week. Checked in at the Santa Fe and told we were booked in for four nights. I checked our return train tickets and yes, we were due to go back on the 8th... not the 7th as I had wrongly got in my head! Meant I had to do a bit of hand washing clothes in the room as I had cut our luggage down to the minimum but otherwise a lovely surprise.
At least you found out before then! Enjoy the bonus.