I accidentaly clicked unsave
Any answer to this question requires detailed information about your operating system, your filesystem (NTFS, whatever on Linux, HPFS or APFS on macOS). Since you clicked not to save your document, file entries from the directory structures have been deleted and only low level recovery utilities could find and recover the data. And: To increase the probability for such tool being successful, you should stop using your computer now, since each write performed may overwrite the now released sections of your hard disk containing the fragments of your data.
If your document was saved once in the past and you (luckily) had activated Tools -> Options -> Load/Save -> General -> Option: [x] Always create a backup copy then you may find a backup copy in what your Backups-Paths tells (Tools -> Options -> LibreOffice -> Paths -> Type: Backups). But this won’t contain your recent changes.