I'd find something, anything, that makes you laugh until you cry/wheeze/snort. Even if that's weird humor: I've got friends who go in for kids' cartoons, and others who watch stupid youtube stuff. Depends.
Another thing to do is read other people's stories. For me, I use
Love Gives Me Hope and other heavily emotional sites. If you're stressed out, seeing that others are/aren't stressed often will give perspective. Helps me, anyway!
The last and best thing is to grab a good friend, and treat 'em to coffee (or a can of soda, if you've only got a few minutes). I mean a GOOD friend, someone you can just gush out, and who'll help you. A parent will also work well sometimes, or an SO. Someone who'll listen is all you need to get the stress off. Helps you feel like you aren't alone... cause you aren't! You've got all of us! :D
Hope this helps!