In Act 5 of Macbeth, Lady Macbeth certainly shows that she feels alone and isolated and is now suffering mentally from the acts that her husband has performed behind her back. Lady Macbeth cannot believe that Macbeth has gone so far as to murder Lady Macduff and her children, and this event is one that pushes Lady Macbeth over the edge. She says, "Yet who would have thought the old man to have had so much blood in him" (V.i.37-38) when she thinks about all the ill deeds that Macbeth has done.
In addition to this, Lady Macbeth also shows that she is feeling isolated and anxious earlier in the play when she covers up for Macbeth at the banquet. When Macbeth made the plans with the murderers, he left his wife out of the scheme and told her that he needed to be alone. When he hallucinates the ghost at the banquet, Lady Macbeth senses that he has done wrong but she is not sure what deed has been committed.