Hi @SecretSanta
You should search your device first and see if you still have a Local Sites folder anywhere because your site files might still be there just shifted. If you can find them you can reimport the site back into Local.
For future reference you can always back up your work a few different ways. You can use our Cloud Backups Add On:
You can use Local’s native export feature to export a zip copy of your site to save on your external or Cloud Storage:
Or you can use any number of backup plugins to do something similar to the above as well.