I survived Day 2. There were some undeniable flying-by-the-seat-of-the-pants moments (when my lesson plan that successfully filled eighty minutes for two of my classes only took about half-an-hour for the third class and I suddenly found myself having to wing it for a huge chunk of time), but I managed to maintain a convincing-ish front of acting like I knew what I was doing, and all went reasonably well.
Another notch. A couple hundred-ish more to go, and I will have survived Year 1. Onward and upward.