At the end of the day, happiness, is a choice. You CAN be "happy" right now, but if you're " putting on a happy face" to appease the day, the thought is always going to be in the back of your mind, which, in my opinion, is a worry.
It's true that "worry" is an unproductive approach to making life better, but the truth is, it is all in how you direct your energy.
If you make a 100% decision to tackle life with trust and without worry, you will get back what you are putting out.
I think that if you WANT to be happy, you will CHOOSE to be happy.
If you CHOOSE to be worrisome then you will fill YOUR day with unproductive thoughts.
It's a choice. And, only YOU can decide what is or isn't allowed to accompany your happiness,