I doubt if anything can be done about the project at this point, but if you can't recreate the worksheet data maybe OriginLab support (tech@originlab.com) can retrieve it from the file.
I'm afraid that you'll have to bite the bullet and start over. Next time I'd try a more manageable subset of your data and try various methods of saving the project in a state where it can be reopened. In an earlier post you said that after you created each graph you hid it with "win -h 1;". Try minimizing it as well... "win -i; win -h 1;" and just before you save the project type "doc -e P {win -i}" in the script window for good measure.