In this scene, Lady Macbeth is mentally unraveling. While sleepwalking, she obsessively tries to wash imaginary blood from her hands and speaks to her absent husband, Macbeth.
For your reference, here is the immediate draft of that section from Shakespeare's Macbeth : come_give_me_your_hand
To bed, to bed! there's knocking at the gate: come, come, come, come, give me your hand. What's done cannot be undone.—To bed, to bed, to bed! Analysis and Modern Usage In this scene, Lady Macbeth is mentally unraveling