
you may have made a crucial mistake. Prepare for the worst.
Did you open the .rar file as a mail attachment?
If you did, your work is gone. It is not a WinRAR Problem but a general WINDOWS flaw. Any mail attachments are opened as temporary files. When you edit them the changes are saved in the temporary file. When you the finish your work, WINDOWS deletes the temporary file and the changes within... SORRY MAN!
If you don't want this to happen again, DONT WORK WITHIN MAIL ATTACHMENTS. Save the attachment first, then work with them!