The excerpt suports the conclusion that Brutus is considering taking his own life.
In this scene, Brutus asks Volumnius to come closer to him, to tell him that he has seen Caesar's ghost two times at night, one at Sardis and the other at Philipi fields. He interpretes it as a message, and realizes that his time has come, since enemies have almost won. Eventually, he decides it is better to die by his own means that to let his enemies kill him.