I change a file in excel and and need to get the old version

[Michael]

I used my last years budget as a template for starting this years budget. I
made cell $0 and then accidently hit the x button instead of the - to shrink
it. Office didn't ask me if I wanted to save the changes and now I don't have
the completed version of last years budget. What do I do. Please help
!!!!!!!!!!!!!!!!!!!!!!!!!!