In Act 3, scene 2 of Shakespeare's Macbeth, what evidence is there in the text that suggests Macbeth suffers a guilty conscience?

In Shakespeare’s Macbeth there are
many instances of Macbeth’s guilty conscience.  For example, in Act 3, scene 2, he says
to Lady Macbeth, “We have scotch'd the snake, not kill'd it.” (3, 2, 15)  This of course
is in reference to his killing his King and feeling as though he is too far gone into
his plans of destruction to make things right again.  He is no longer able to sleep
well; he is constantly stressed, and admits that his mind suffers greatly.  Macbeth also
admits to envying the dead king because he is now at rest.  In this same scene, he has
plans to murder his close friend Banquo fearing that his sons will be kings and fulfill
the same prophecies as were given onto Macbeth.  However, this time he does not include
his wife in his murderous plans.  He tells her to “Be innocent of the knowledge, dearest
chuck”. (3, 2, 50)  Because he is already stressed and troubled with guilt, he does not
want to impose the same fate and troubles onto his wife.