Last night, for example, held one of my classic nightmares: a new classroom. This one was on the fifth floor (my school only has one level) with only one "working" stairway that was missing a railing. When I finally got to my room (many of these nightmares have me running late due to circumstances beyond my control), I found most of my students sitting on the narrow landing to the stairs, looking down five flights through broken pipes and wires. They weren't in my classroom because the classroom was only about fifteen by twenty feet and filled with old materials from other teachers' classrooms. We moved the stuff around as best as we could, but before I could start teaching, the bell rang and I had to go back down the treacherous stairs to get to a different classroom (I've only been in multiple classrooms one year, and I hated it).
That's most of what I remember (aside from something about a blizzard, parking problems, and MacDonald's coffee), but you get the basic idea. At least I was teaching (or going to teach) in my subject area. I have had dreams where I was teaching chemistry, biology, and even Spanish II (not Spanish I, but Spanish II).
It's a little early for the dreams. They usually wait until early August. They probably started early because I met with my new student teacher last week. I could do without these nightmares. I have enough self-doubt as is.