So after all of the angst I had yesterday and last week about my "disaster" class, today's class went really well. I got my groove back! I wrote an assignment, and while it's not my best, I think it's pretty good, and the students seem happy enough with it (well, as happy as they can be with a homework assignment).
Sometimes, it pays to take a step back, take a deep breath, and be patient, because things have a funny way of working themselves out. Not always, but sometimes.