I get this guilt dream too - often that I have not prepared for my History finals (read Languages, not History) or maybe Lit. I wake up sweating that I have tried to blag my way through them!
I alos still dream about school, usually the night after I have had some contact with old colleagues, and my "favourite" nightmare is that I have a register in front of me, can't read the names and looking at the faces, do't recognise my own Tutor Group.
Clearly need to get out more 