Answer:
He was so exhausted with the bloodshed caused by his actions that he was almost immune to the pain of death.
Explanation:
Lady Macbeth's death left Macbeth in an extreme state of despair and misery. He wishes that she should have lived "hereafter" and speculates the brevity of life. His soliloquy of "tomorrow and tomorrow" is representative of exhaustion of life and absorbed with self-pity. He was a man of hopes who has turned into a depleted individual who is now pondering the immortality and meaninglessness of life. He was so distressed and taken aback by the carnage that death was now impotent to his immunity.
