Continuing my regular workout on the road keeps me sane. I don't get on a plane without the tech support numbers for every machine, hotel and service I'll be using on the trip. It's a pain to collect the numbers, but it's a bigger pain to track them down from the road. A little imaginary thinking can spare you a lot of grief. I carry energy bars for the plane and never schedule the last plane out of a city.
Contingency plans are the only way to fly.
You know they will. So leave your perfectionism at the office. Our winning strategy for dealing with a boss who'd give a lousy reference comes all the way from Middle East, from Dubai, United Arab Emirates to be exact. So you may or may not get a favorable reference. I am sure honesty at a time like this would not only clear the air but would also tilt his assessment of you in your favor.