Spread sheet duplicated right next to itself

Somehow I duplicated a spreadsheet...that is to day the spreadsheet with all its rows and columns, appears right next to itself (separated by one blank column).
Not sure how I did this...I think I was trying to freeze and unfreeze columns and rows. Not sure how to delete it because it is an exact duplicate, when I highlight all the duplicate rows and columns, they are also highlighted on the original columns and rows. So it is acting as an exact duplicate. How do I delete it?