Why are my SQL Server backup ending as a file that is twice the size of my database?
Most likely, it's multiple backups inside the same file. To see it:

RESTORE HEADERONLY   
FROM DISK = N'N:\MSSQL\DATA\CC\CC_backup_tues.bak' ;


If you see multiple backups in there, you have a couple of different options:


Specify a different file name per backup (I'm a huge fan of this - use date-based file names rather than days), or
Use the WITH INIT command to overwrite the last backup - this can be a bad idea if you ever need to go back more than a week