It may seem hard to believe (for some), but you can choose joy in every moment. You have control of how you generally and primarily feel emotionally, because you have agency over the necessary components of your body-mind to self-regulate and determine your focus. This takes quality practice to master, but it can effectively be done.
To get started, you can choose to practice emotional flexibility, feeling all of your feelings as they arise and appropriately responding when/if necessary, before letting them go and getting back to your baseline of joy: there are many self-guided and self-sustaining ways to do this; you simply have to find a way that works well/right for you.
Yoga-Meditation Lifestyle Wellness 