Excel ERROR Message

[gillman1500]

Hey everyone, so I was making a pivot table in Excel and I wanted to delete it. I highlighted the pivot table and hit delete on my keyboard. The error message is "Cannot enter a null value as an item or field name in a PivotTable report." I close the error message and any time now I click on ANYTHING in excel this error message comes up. I can't close the window, unhighlight the pivot table, or even hit file or save. Please help me, I have to get this excel project done by midnight and I am 3 hours through it. I'm running excel on a Mac book through a remote desktop connection.