When you open the project does it warn about missing media files? If so, then is has some info which might be corrupted but might still be useful.
The .md8 file is just XML, so you can open it in a text editor and search for one of you filenames. If you find it, perhaps you can compare the path in the XML file to the actual path and figure something out.
If you don't get any warnings when you open the project file, then it probably lost track of your clips. However, the layers might still remember which media slot was loaded (when selecting layers, do you see the orange highlight moving around in the media panel?) so if you can figure out what layer was what, and drag the correct media into the orange square, it might pop back up with all of the layer settings preserved.
M8 itself does not keep any backups and does not have a way to rewind to previous versions. Unless you have Time Machine or keep your project files in Google Drive, then you have to just try to fix forward.