Happiness refers to the way that someone feels and a positive state of mind. What makes someone happy depends on the person, and each individual may have different forms of happiness and thoughts on exactly what it means. Usually happiness is spending time with loved ones, although for some money is what makes the world go around for them and they will never be happy because they always want more.
Don't stress over what you can't control. Just let it be and focus on being happy.
You know it's love when someone's happiness is more important than your own.