tetanus vaccine - effective after injury?

krismc68

I am new to the board and had a question. 2 nights ago i stepped on a piece of wood ( from a wicker basket think) and it got stuck in my foot. The next morning i went to my doctor and had it extracted. he also gave me a tetanus shot since it was a puncture wound. Now this morning when I woke up I feel sore and tired. I am worried if it could be tetanus ? I have not had a shot for 20 years before this. when should I start pancking?? Please help!