To counteract this, I usually listen to at least some of the previous weekend's "Wait! Wait! Don't Tell Me!" (from NPR) that I record for my beginning-of-the-week drives. I had discontinued the practice last year unless I was driving alone, but now Mera (my Prius) can play them on her speakers so we can both listen. The combination of refreshing my mind of the previous week's news and lightening my soul with entertaining wit makes me feel genuinely prepared for the beginning of a week.
Truthfully, nightmares aside, I love the first day of school. At no other time in the school year is there such an air of anticipation and determination. Students arrive ready to prove themselves, to do better than they have ever done in the past. Often, this energy wears off as the weeks continue, so I like to soak it in as much as possible on this first day. Also, many of my students from previous years stop by to say hello, shake hands, or even give a quick hug. It's usually on the first day that my previous students will sagely advise my incoming students about doing their work in my class and how to get on my "good side."
I am exhausted, but it's the good kind of exhaustion. The kind of weariness that comes from knowing that I have a great job and get to deal with fantastic people. Here's to another wonderful school year!