What is the difference between sadness and depression?

The difference between sadness and depression is: Sadness is a feeling due to circumstance. Depression an ongoing condition that persists for two weeks or more. Say your dog dies. You will be sad of course! Probably crying and chocolate will ensue. Your heart breaks. You lean on friends or family during this time or things that nurture you. Yet you’re still able to enjoy things like food, sleep and activities. Your other aspects aren’t clouded over by a persistent toxic cloud. Depression is like the moment of sadness twisted into a never ending story. The sadness rolls like a snowball down a hill, picking up more and more sadness.