Depending on the age of your child they will grieve for a while. think of the dog being like a best friend to your children and now their best friend has been taken away its almost like as an adult losing a parent.
Sadness is a cause of a certain effect that will go away once the person heals, chronic depression has no cause, the person is depressed for no reason and it's not easy to heal.
Depression
Depression sadness
Depression.
depression
depression
Sadness.
Depression is the feeling of how a person feels with and extreme length of sadness.
depression
unhappy depression and extra.
probably do to depression sadness
melancholy