The difference between happiness and joy is a matter of root cause. Happiness is tied to the happenings of our daily lives. Are we happy with what is happening and what we are experiencing? Joy is an intrinsic pleasurable feeling rooted in our knowledge and understanding that God loves us and uses all things to work for our good.
Life is one of the greatest gifts we could have ever been given. It is our birthright as human beings to enjoy our lives in all ways without harm to ourselves or others.
Do you have a positive awareness about who you are and your intrinsic goodness as a human being? God sees you as very good, and from this perspective you can count all of life's experience as joyful.