Excel overwrites vital data

[Hill Hughes]

I track my self-employed hours of work and details of meeting on an Excel file.  Each week I create a separate tab.  Today I copied and renamed a tab for this week's work and began editing it.  

To my horror, the edits I made on this week's tab were replicated on all (40+) tabs.  It looks like all that data is lost.  

Is there a way to recover my old information?

Thanks

[Computer_Commando]

If no backup file, all data is gone.