What causes Romeo to become so upset when he speaks with the nurse?

When Romeo speaks with the Nurse in Act II, Scene 2 of Shakespeare's 'Romeo and Juliet,' he becomes extremely upset because she delivers news about Juliet's marriage. The Nurse informs Romeo that Juliet is to marry Paris on Thursday, which devastates him. Romeo's emotional response to this news stems from his deep love for Juliet and the fact that this marriage will prevent him from being with her.