Initially, some of the things that you've done, that contributed to your unhappiness, you probably thought at that time it would be good for you. But after you saw how disruptive those thing were, you should have quickly stop doing them and try your best to do something positive. Finding ways to do positive things in your life will improve your health and state of happiness. And also fill your life with enrichment.
If the things you're doing in your life is making you happy, there's no need for you to abandon them. But that don't mean you can't incorporate other positive things into your life style that will enhance the things you're already doing, which will make you even much more happier than you already are.
Eating right and exercising regularly is two of the most positive aspects of self preservation you could ever practice! Practicing those two things will help you with you mental and physical health, which inturn will help you with your state of happiness. Happiness is a positive emotion that will help you with your mental and physical health. So! From my perspective, HEALTH and HAPPINESS goes hand in hand. HAPPINESS improves you HEALTH. Your HEALTH embellishes your state of HAPPINESS. Happiness comes from within! Your health and happiness begins with you! No one can make you happy, but you! No matter how hard someone else try to make you happy. If you're not happy with yourself, It's more than likely they won't be able to make you happy!