External factors that affecting happiness are highly unsustainable. Being grateful and appreciative present moment helps promote inner happiness, and from time to time, we need to seek verification within ourselves--what is it that really makes us truly happy. I believe it is something which is within your control.
Happiness should not be a goal. If your goal is to be happy, you'll never attain that goal. The point is to be grateful for the blessings that come your way. Being grateful is a habit to be cultivated. When you are happy and grateful, that's just a bonus. According to Descartes, happiness doesn't really exist, but satisfaction is something solid, and that is what one has to seek if one is looking for something durable.