My Passport - file access incredibly slow

I’m an freelance Management Accountant, My Passport 500GB used to store only data files, small sizes, Excel spreadsheets mostly. Sometimes when I try to open a file from Windows Explorer, I could go off and make a cup of coffee for the entire staff, come back and it’s still not loaded.  Ok, slight exaggeration but not that far from the truth.  Any ideas why this might be?

Hi there, I can be a sign that the drive is close to failing… What if you run a diagnostic to it and take the files out if you don’t have a backup?