Argh! backup?

Help! I make regular backups (I did so yesterday) but just now I have accidentally deleted the contents of my entire document. To my shock and utter surprise all 52 pages are fini, gone, kaputt! I don't know what happened, probably hit the apple+A and then typed without looking, or something...grrr.(plus hit apple+S, duh)
Is there a way to retrieve what I made today or is there no alternative but to start back from where I ended yesterday when making my backup? An autobackup that's hidden somewhere?
all help highly appreciated!
Elszy