MacBook Pro automatically reverted back to previous save from month ago, now missing all saved documents.

I do not have time machine ...

All Macs have had Time Machine, for over a decade now. You do have to turn it on though, which is accomplished with a single click in its Preferences:

Notwithstanding that uncertainty, try the following:

1. Boot macOS Recovery.
2. At the Mac OS Utilities screen, select "Restore From Time Machine Backup" > Continue. A Restore from Time Machine screen will appear. Read it then Continue.
3. When the Select a Restore Source screen appears, select the internal disk. Its default name is "Macintosh HD" but you may have changed it. Continue.
4. The Select a Local Snapshot screen appears next. Restore From > Local Snapshots on Macintosh HD (or whatever you named its startup disk) will appear in the dropdown menu selection.
5. If a Local Snapshot Date & Time list populates, select one that corresponds to the version you want to restore. Continue.
6. A confirmation dialog will appear. Read it then Continue.
7. A Restoring screen will appear next. That operation won't take long.
8. A Success screen will appear next, and the Mac will restart.