Happiness is what's behind all the struggles. I personally believe that every want, need, pursuit of love, luxury, money etc are all driven by the desire to be happy. Our pursuit to make money is driven by the desire to live happily. Sometimes we may wonder why someone will be rich and still be unhappy. That is a clear evidence that happiness isn't tied to material things.
Happiness is characterized by involving positive emotions and life satisfaction<
Take for instance, one may be feeling very down due to some challenges and the next day, the same person is already all cheered up and filled with lots of positive energies. It's not like the person got all his problems all figured out within 24hrs but definitely something happened to change his mood. Personally, I will tell you that it's "acceptance". Happiness, comes with acceptance. The more you start accepting situations you can't change, the more happy you will become. No one has it all figured out but the difference lies in acceptance. Acceptance creates room for appreciation and when you start appreciating, you start being greatful and when you are greatful, you tend to be happy.
We all most have lost some things in the past be it money or someone we love. The reason we mourned for days, weeks, months or years is that fact that we are finding it difficult to accept that those things are actually gone for good but once we start accepting that fact, we start being happy. You find happiness in accepting life the way it is when you must have tried your best to put it the way you want.
May we all find happiness.