I think you've simply lost your whole proggress in that race, you should not have chosen "No" when it asked you to resume the race, since the game just interpretates that you don't want to do it anymore. Good luck for the next race :/
Erm, think I've ****ed up here, 15 hours into le mans 24 hours, sign back in, "resume race?" I select no, no warnings, off I go and download the new tracks etc.
Try to resume the race, no longer there. Have I lost it ? Surely the saved file is there somewwhere