Formating issue

I am using Firefox and in my training log, at the top I pasted in an Excel spreadsheet cut.  If I am in edit mode things line up perfectly.  But when I am reading my blog out of edit mode the first half of the spreadsheet is not lined up correctly.  Monday gets shifted over to Tue but only for half the spreadsheet.  Since it looks fine in edit mode I can't figure out what to change to make it work correct.  I pasted it into Word for giggles and it formatted just fine there