How we feel is something inside us , a wheel that keeps on moving. Just watch it--and it is very beautiful, because in being aware of it, something has been attained. Now we understand that we are free from outside excuses, because nothing has happened on the outside and yet our mood has changed within a few minutes from happiness to unhappiness, or the other way around. This means that happiness and unhappiness are our moods and don't depend on the outside. This is one of the most basic things to be realized, because then much can be done. The second thing to understand is that our moods depend on our unawareness.
So just watch and become aware. If happiness is there, just watch it and don't become identified with it. When unhappiness is there, again just watch. It is just like morning and evening. In the morning we watch and enjoy the rising sun. When the sun sets and darkness descends, that too we watch and enjoy