How does Madame Loisel react to the invitation?

Madame Loisel's reaction is completely negative. Her husband believed she would be thrilled with the invitation, only to have the invitation thrown in his face. Madame Loisel cried and carried on because she had nothing to wear.

Madame Loisel throws away the invitation. Saying that she would look funny and poor around all these rich people, she argues about what to wear for the ball.