How does Macbeth feel about having murdered duncan?

After murdering Duncan, Macbeth is consumed by guilt and remorse. He is unable to sleep, and when he does, he is plagued by nightmares. He sees visions of Banquo's ghost, and he hears voices that accuse him of murder. Macbeth becomes paranoid and unstable, and he begins to spiral out of control. He is no longer the confident and ambitious man that he once was. Instead, he is a shadow of his former self, haunted by the guilt of his crime.

In one of his soliloquies, Macbeth says, "Methought I heard a voice cry, 'Sleep no more! / Macbeth does murder sleep!'" (II.ii.33-34). This shows that Macbeth is not only unable to sleep, but he also feels that he has killed sleep itself. He feels that he has committed a crime so heinous that he has disrupted the natural order of things. Macbeth also says, "I am afraid to think what I have done; / Look on't again I dare not" (II.ii.50-51). This shows that Macbeth is so horrified by his crime that he cannot even bear to look at it. He is trying to repress the memory of what he has done, but it is impossible for him to forget.

The guilt and remorse that Macbeth feels after murdering Duncan are ultimately his undoing. They lead him to become paranoid and unstable, and they eventually destroy him.