Answer:
Well Depression is always present regardless if something/ someone caused the "sadness". For example if someone made you sad you probably would start feeling better after a bit of time goes by, but with depression you are constantly feeling down. If feelings of sadness don't go away after about two weeks then that is a sign it may be something more than just sadness. Also, depression is a mental illness not just an emotion that comes and goes. Your Brain chemistry can also change along with a depression diagnosis.
Depression consists of:
Constant feelings of sadness
irritability
fatigue
changes in eating or sleeping patterns
difficulty concentrating
loss of interest in things that were once pleasurable
feelings of worthlessness
feelings of deep guilt
and much more
Step-by-step explanation: