Dear T,
I'm terrified for tomorrow's session. Maybe I shouldn't have sent that email. I want to email you to ask for reassurance but that'd just be pathetic at this point since I see you in like... what, 30 hours?
I also want to cancel or not show up so I don't have to see you but that'd be stupid and inconsiderate and would just delay the inevitable.
Please be gentle about this.
-c