A format option (I mean quick format or complete format) won't erase the files on your WD drive "permanently" at least for quite moment until the data overwritten. You saved more files, then chances of recovery might be reduced to some extent BUT not necessary to overwrite. So you should act as quickly as possible. Take a try of this WD data recovery software, it should help you out. Regards.
I formatted my wd passport and save some new files but now i need my old files back...
if there is any possibility to get my old files... pls reply to email@example.com
If you have added new files to the formatted wd, it may be a little difficult to recover the old files, but you can try the wd data recovery software, it is a professional and effective software to recover data after format, delete and more other reasons. Good LUCK!