What makes you happy? Do you know? Have you set a happiness goal?
Many people are never happy even though they have achieved success. Why? In my opinion, it's because they've never decided in advance what defines their success and consequently, what it takes to make themselves happy.
It's important to have a clearly defined goal. For me, that goal was to complete a coherent novel with a beginning, a middle and an end. I did it. Therefore, I am happy.
This doesn't mean that I will stop at that point. It does mean that I will set a new, clearly defined goal of happiness. My next happiness goal is to get an agent to represent me and my works.
Some day, if my novel reaches best-seller status, I will be happy too. If it never reaches that point, I will still have experienced happiness.
Take the time to set a clearly defined happiness goal. You'll be glad you did.