Happiness is a state of mind, it exists within. Most of us just don't know where and how to look. We let our happiness be determined by external factors, uncontrollable ones. We let friends, family, lovers et al be our 'happiness determinors'.
In this life I've learnt that you can't find something if you don't know exactly what you're searching for. Hence the need to sit down and write about past experiences that enabled you feel true joy, those memorable moments you relive on quiet Saturday afternoons with doors locked and room quiet with curtains closed and everything switched off; yes, those moments. Focus on experiencing those happy moments again, or new experiences that will make you feel equally good, or better. Avoid searching for happiness in the wrong places; it is like chasing the wind or fishing smoke. I believe happiness is our birth right.
So smile, don't worry, be happy. You choose what dominates your thoughts, hence your feelings. Always remember that.