Funny how it only takes one day to get a baby off schedule and weeks to get them back on it.

All I can suggest it that you don't try to change it back overnight. Try to readjust it gradually...10 min per day. Go ahead and start working towards the upcoming time change too. Plus, understand that his patterns will continue to change--the routine schedule you were used to will probably not remain a constant. I remember that my daughter didn't relaly get with a set routine and stick with if for more than a month or so until she was about 2!
Most importantly, just hang in there and when you feel like you can't...come here and complain and let it out and we'll all help you!