Are you referring to clearing the caches through the option in Settings or clearing the actual system cache partition? They're two different tasks, the former being the app caches for user apps that you've installed and the latter being the protected operating system cache. If you haven't cleared the system cache partition it would be something to try to see if that helps fix your Application manager problem. The system cache is separate from your app caches so wiping it won't affect your personal data or any settings you've made to your apps. You need to boot your Note into its Recovery Mode to do this:
http://www.solvemix.com/index.php/a...-to-perform-wipe-cache-partition-instructions
You might also want to use a web browser, log into your Google account, and check what apps you've installed recently. I don't think something you've installed will affect the Applications manager on your Note like that but take a look at anything you've installed recently. Maybe a utility that alters/enhances your phone's menus or something like that? :
https://play.google.com/apps
You mentioned this problem starting about 3 days ago, can you think of anything that happened on your Note just prior to that? A system update maybe?