Drop is the opposite of Flood. Person does not want (to) Flood. Married is a type of Person. 
Drain is a type of Empty. Drain is similar to Fatigue. Thinking can cause/lead to Fatigue. 
Drop <--Antonym--> Flood <--NotDesires-- Person <--IsA-- Married 
Empty <--IsA-- Drain <--SimilarTo--> Fatigue <--Causes-- Thinking 