Hello all - hoping someone can help me!

I've created a workbook with multiple sheets within. When saving the spreadsheet - for some reason I saved as an XLA file, and this converted my original. In doing so I seem to have lost all of the structure to the file, ie: Sheets.

Is there anyway that I can revert back to the xls file, so that I can restore the sheets and the work within the sheets?

Thanks in advance! Neil