Basically, reducing the impact of emotions as much as possible. You can still feel it, just don’t let it affect you. Never let emotions take control of the self.
YOU DO NOT COUNTER IT WITH DOING "DISTRACTION" ACTIVITIES LIKE DOOMSCROLLING. No need to “cheer up” blah blah blah. You counter it with action that directly destroys the source, or comes as close as possible to reducing its impact as possible. While doing that, you should also do things like meditation to avoid letting unhappiness negatively impact the ability to solve problems. And you should also treat it as natural, while there can be happiness, there can also be unhappiness. At worst, for things like death, accept that it is what it is: Amor fati
Emotions are confused thinking, and it's better to understand nature through logic and reason. Emotions lead to trouble from impaired judgment. Thus reducing their influence, for instance by stoicism or asceticism will help out. Psychologically, Human emotions cause interference to logic! I think it’s just the brain’s panic response activating, and dangerous wild animals don’t need your brain to think logic, but that danger has mostly disappeared yet our stress responses remain the same due to Darwinism: The most careful lived. Thus, the brain simply cannot properly reason if you sense it’s “burning sensation” or you are feeling hyper or angry at a particular moment.
And there’s also the need to factor in others’ emotions as well, to an extent: Just because you don't feel much wouldn't mean other people would have the same reaction. When I was little, I was still in emotional immaturity, perhaps due to my shyness, and it impaired my judgement because I wanted too much ego, and the "looks" of emotional stability, even when I felt pain inside, which led to stress.