Make Auto Backup File When Opening

I want to make a macro that will generate a backup copy each time the Excel file is opened. I premade a backup and recorded the following macro, placing it in the sub here:

Code:
Private Sub Workbook_Open()
ChDir "C:Usersmy.selfDesktop"
ActiveWorkbook.SaveAs Filename:= _
"C:Usersmy.selfDesktopDaily Backup.xlsm", _
FileFormat:=xlOpenXMLWorkbookMacroEnabled,_ CreateBackup:=False
ActiveWorkbook.Close
End Sub

names have been changed to protect the innocent. But now either putting in to repoen the original working excel or manually opening it puts me in an infinite loop of backing up. The probelm seems to be that to make a copy it is making the open workbook the backup. So two part question here:

1. Can I make a copy under the same name automatically when the file is opened while staying in the current one?
Example: open the Excel file "Working Copy", which makes a mirror file called "Backup Copy", but stay in "Working Copy".

2. From what I did manage to do, I notice every time it asks if I want to overwrite. I chose "Yes" when recording the macro but this doesn't seem to get captured. can I make it automatically yes without being asked?