The development team has acknowledged that there is a problem with game save loss/corruption and has offered to help. Unfortunately there’s not much we can do here on the forum besides pointing you to an email address, and this recent post by HeliosT10 who is on the Development Team:
You’ll get an automated reply from this address but be patient and someone will try to help you.
If it’s any consolation you’re not very far into the game so it may still be fun for you to start from the beginning again.