The part of your anxiety dream which featured missing classes because you didn't know about them is actually *very* common among anyone who has been through post-secondary education I suspect, and time elapsed since leaving education behind doesn't seem to count. I've certainly had dreams where I suddenly had exams for classes that I didn't know about, or dreamed of failing classes for non-attendance. There also seems to be something odd going about where multiple people over the last week or so have had (and shared) unsettling dreams.

I almost never remember my dreams, for example, and had an anxiety dream last week. I dreamed I was living in my mother's house (and she was much younger than she is now, but I seemed to be my current age). She was angry with me and short in general, and very irritated by the dogs, and I was convinced she was going to throw me out and that I would have no where to go. I actually thought in the dream "... Maybe I could by a house?" and there was this odd lacunae as if it wasn't possible for some reason, and it was as if I had no job and no resources. The dream went on with her being irritated with me, and then I woke up in my own bed, in the house I own, shortly before I was due to wake in any case to go to work. I was baffled, and mentioned the dream to Minion, who told me that she'd been having such unpleasant anxiety dreams lately that it was a relief to wake up. It's not much consolation, but you are far from alone in having inexplicable dreams.