So earlier I said the only things I could think about were food and fear... I've eaten now.
I feel like elaborating is probably a good idea:
Broadly speaking what I have is a fear of failure but not simply failure, it's a fear that I never deserved to be here to begin with. I've spoken to several other people about this and it seems a common theme among a certain kind of person; we fear that at any point people will figure out that we're faking it (whatever 'it' is) and suddenly we'll have to go and get a job in MacDonalds or similar.
Rationally, I know I'm pretty good at what I do and I will likely be capable enough in this job to at least not screw it up... but there's always the paranoid part that doesn't get that and is scared.
That said, the next couple of days at least will probably be administrative and basic training things so I won't know if I have what it takes for at least a little while.
Until then, I will enjoy my B&B stay and try not to get anything too wrong.