I was so clueless that luckily I still didn't realize it up until arriving at work and seeing the hospital clock, so there wasn't any time to get all panicky.
I am one of those crazy back-up alarm folks. Every night I set my alarm clock--which has a back up 9-volt battery for power in case of an outage. On top of that, I use my cell phone as a back up alarm. You would think that the thing would update the time automatically, just like it does when you enter a new time zone on a long car trip. No such luck.
Luckily, when I did get to work there was only ONE patient in the department (A Daylight Savings Miracle!), and the attending that I was scheduled with honestly didn't care about my faux pas.