Macbeth walks boldly into Dunsinane with the doctor and his attendants, bragging loudly that he has nothing to fear from the English army or from Malcolm, since “none of woman born” can harm him and he will rule safely until "Birnam Wood remove to Dunsinane”. He is all worked up, however, but still confidant that the witches' prophecy will hold true and that he has nothing to fear.
He calls his servant Seyton, who informs him that a huge English army is approaching the castle. Macbeth insists upon donning his armour, even though the battle is still some time off. The doctor tells the king that Lady Macbeth is still troubled but Macbeth orders him to cure her of her delusions. The doctor, in an aside, says that no amount of money could make him come back to this castle if he were not already there. The doctor is picking up on the frenzied vibes that are coming from Macbeth.
Macbeth's state of mind, then, is upset and frenzied. He is at a heightened state, worried about the approaching army and his wife's illness (because he knows WHY she is ill), but he is also confidant that no one can harm him, so he is almost flaunting this fact - not only to convince others, but to convince himself as well. You can read the text here at eNotes.