My Microsoft Word file won't open on Mac or Windows...?

I was typing a play on a Macintosh computer and when I went to click save it saved, but when I tried to ex out it asked me to save my work. I saved it many times, and then just closed out, and when i tried to reopen it minutes later the Mac told me I needed to convert the file. But none of the options worked. And then I tried to open it on a Windows computer, and Word can't read it. I really need help. This is a 20 page play that needs to be turned in last week.