I'd caution that what you describe is a lay explanation for one theory of depression and is not definitive or settled science. The word you are looking for to describe your mental status after the passing of your dog is grief, a normal human emotion. Clinically defined depression may or may not have triggers or causes. It is incorrect to state that clinical depression is defined as sadness without a particularly identifiable cause. The presence or absence of a cause is irrelevant.
Curious reply to the lithium question given the data displayed in The ICE Age is Far From Over video from last year. Lithium was presented as the material in least supply and to add supply would require new production and possibly mines, requiring the greatest time to become operational. And you had presented elsewhere as a favorite with copper.
