A. That is water under the bridge. If the stick wasn’t encrypted, it is likely that information will be seen by whoever finds the stick. If you don’t have a backup, the data is lost to you.
Going forward you can protect yourself should this happen again:
- Backup. Always have a local and cloud backup of your data. It must be securely encrypted (FileVault 2 if using macOS, or BitLocker if using Windows), using a strong (15+ character) password that is not used for other sites/services.
- Encrypt. Encrypt every storage device – boot drive, backup drives, thumb drives, etc. FileVault 2 if using macOS, or BitLocker if using Windows.