My Toy Poodle Ate a Chocolate Bar, What Should I Do?

Oh my goodness. Two days ago I found a hershey's milk chocolate wrapper(empty) by my toy poodle's dog bed. She weighs 12-13 pounds. The chocolate bar was one of those halloween ones, small. Now right now she's shivering like crazy! My parents aren't home, and it really looks like she's in pain or sad.