When I'm depressed it comes with other physical and mental symptoms. Usually lack of energy, want to sleep all the time, cry over nothing and generally I just don't give a damn about anything (except my kids of course).

I can be in a bad mood and not cry; or be in a bad mood but still have energy for the day to not sleep.

Or; of course; I can get in a bad mood when I'm depressed; but then it will come with the other symptoms I mentioned above.