Macbeth is tormented with his guilt. He cannot sleep. In fact, he repeats that he will never sleep again in Act 2 , Scene 2:
Methought I heard a voice cry 'Sleep no more!
Macbeth does murder sleep,' the innocent sleep,
Sleep that knits up the ravell'd sleave of care,
The death of each day's life, sore labour's bath,
Balm of hurt minds, great nature's second course,
Chief nourisher in life's feast—
Also, Lady Macbeth comments on the disturbed feelings of being King and Queen. She states that there is no content in being King and Queen. In Act 3, Scene 2, she contrasts her discontent with the joy that the one they destroyed must be experiencing:
Nought’s had, all’s spent. Where our desire is got without content: ’Tis safer to be that which we destroy than, by destruction, dwell in doubtful joy.
Macbeth cannot clear his conscience and Lady Macbeth repeatedly tries to wash the bloodstains from her hands.
In Act 3, Scene 4, Macbeth sees Banquo's ghost and begins talking out of fear. He is an emotional wreck.
The GHOST OF BANQUO enters, and sits in MACBETH's place
Here had we now our country's honour roof'd,
Were the graced person of our Banquo present;
Who may I rather challenge for unkindness
Than pity for mischance!
His absence, sir,
Lays blame upon his promise. Please't your highness
To grace us with your royal company.
The table's full.
Here is a place reserved, sir.
Here, my good lord. What is't that moves your highness?
Which of you have done this?
Clearly, Macbeth is losing his mind. He sees Banquo's ghost sitting in his seat of honor. No doubt, Macbeth is extremely troubled. Being King is not as he dreamed it would be.
Its not Macbeth who wants to be the King but its his wife who brainwashes macbeth to follow wrong paths and to kill king Duncan so that he can be the king. His wife just wants all the power and money thats why she wants macbeth to kill duncan and be the next king.