Why is merry so despondent at the departure of the Army of the West?

Merry is despondent at the departure of the Army of the West because he feels a deep sense of loss and uncertainty about the future. He has formed strong bonds with the members of the army and is acutely aware of the dangers they face in the battles ahead. Additionally, Merry's sense of purpose, camaraderie, and belonging is severely shaken as he grApples with the potential for loss and the isolation that may follow their departure. This emotional turmoil reflects his profound connection to his friends and the perilous journey they are undertaking.