It’s funny that it doesn’t, because Mail saves what you’re typing in an e-mail as a draft without asking you.
I’ve been fried on my PC at work so many times, I save automatically every two or three paragraphs as a habit.
You should be able to get Office for Mac on campus for about $10. It has an awesome format that’s not in the PC version called Notebook. It can record class lectures at the same time it formats your typing into an outline form. Totally handy. I use it at work every time I go to a training session.