At the risk of stating the obvious there is a difference between clinical depression and feeling miserable.
If you have been diagnosed by a qualified doctor as being clinically depressed get someone who hasn't to walk you through the options.
If you are feeling miserable it's possibly for a reason that you can take direct action to resolve without flipping your brain chemistry around with pills and herbs.
The "happy thing" is over-rated and over sold.
To truly appreciate what should be rare moments of joy it's natural to feel unhappy for periods and rather indifferent for longer stretches.
People in a state of perpetual glee are A) insufferable to say the least and B) almost certainly insane.
If you are under a perpetual debilitating cloud which arrived without reason and refuses to lift even when it makes sense that it should, that is when you might need a mood stabiliser.
Perpetuity is the key. If your mood will not budge up or down regardless of what is happening to you, you probably have a problem of some kind.
But as I say get a Doctor or three to look into it but I wasn't fibbing about the negative ions.
They can work wonders.