If you haven't setup autosave and auto backups, why not? They are there to help in situations such as this.
You should always have a backup regime setup - using both the inbuilt system, and also one of your own making, such as backup before every major change and make a copy off site.
It always amazes me when people complain they have lost their work when, if it is so important, they should be delibereately saving and backing up as much as possible.
I sincerely hope you have a backup or autosave. If so, they are in the same directory as your project - just rename to 'whatever.capx'.
If not, then this is a harsh lesson indeed, unfortunately.