You could always define what you mean by "things" give examples etc. If you are reffering to an object you could say item instead. If you are reffering to a task you could use the words tasks, activity, goals etc.
Explanation:
A good way for replacing words is looking up synonyms :)
one factor would be his wife Lady Macbeth and another would be the fact that he knows the future because of the 3 witches and he gets scared of what is to come.
