ACK!!! Day 9 - need TETINUS SHOT?

OH good grief... I'm on day 9 and SOOOO close to being done when WAM, I slice open my finger with something rusty. *sigh* haven't had a tetinus shot in like a billion years, and apparently they expire after that long so... Will I get sick? Is this ok? Someone please reply and set my mind at ease! Thanks:)