Did you hit the back button? That has gotten it back for me in the past. Might this be a lesson learned . . .
Don't actually design your template on auctiva and always save your work often. There are plenty of freebies out there you can use or at worst use the practiceboard and click the url after each change. If something happens go into your history folder and it will be there
There should never be a reson to be in this spot again, be preparred