Macbeth has achieved his ambition to be king. His worries have not ended. What may be some of his concerns now?

that there were stuff that weir going on that this was not going to end

What concers him now is what the witches has said to him in the beginning. They told that you will be grateful for what you get but will not be as happy as his friend (forgot his name). He is worried about his generation not being able to become king after him, since he has no sons that will take after him also what worries him is that he knows he is no the real king and he killed the original king; he knows that sooner or later he will be overtrowned by the dead king's son.