How can I be happier and healthier?

Maybe you need more motivation to avoid eating the junk in your house.

Also, if you are the only person in your household who eats healthy, eating differently from everyone else may seem less fun.

Try creating your own world of a healthy culture through social media because this may give you a sense of not being alone in your effort in healthy living.  

I know some people do better when they don't have as much junk food in the house. This is not as tempting then. Having said that, maybe you can reward yourself with different things, such as having dessert on certain days. If you are concerned about mostly eating habits, consider seeing a nutritionist. They can help you find the balance between what it is that you really want and your goals. I'm not sure how this links to happiness for you, but hopefully looking at your choices can lead you toward your goal of being healthier.