Clearing cache in S-Notes shouldn't have wiped your data. Did you clear the data from Miscellaneous files? If after you did what you did, and S-Notes reverted back to it's setup, then I'm afraid your data is unrecoverable.
EDIT... need to add this...
If you cleared the app cache, and also cleared data, then you won't lose your data unless you also deleted the S-Note data in Miscellaneous files. If you didn't delete the Miscellaneous files data, then you should be able to get your data back. Just reinitialize S-Note, go through the setup, then close S-Notes. The next time you open S-Notes, it will pull the data from the Miscellaneous files and your data will again show up in S-Notes.