I scratched my finger on a 100 year old rusty nail, should i get a tetanus shot.?

Ive been working under a 100 year old hospital putting in a new data system, Its filthy as all hell, muddy and asbestos everywhere. I been scrathing myself nearly everyday on soemthing and today it happened to be a nail that looked like it had been since first built. It only just broke the skin and bled a little bit. I cant even remember when i had my last tetanus shot, atleast 7 years ago. Should i hit the doctors up for one?