I've found that Buddhism has useful stuff to say about this. You can't control the thing that made you feel the negative emotion. But you can work to accept your negative emotions and be more at peace with them and suffer less. That in turn helps you act in a ways that cause less suffering for yourself and others. That helps to reduce the things causing you to suffer, and so on.
This is most of what therapists who lean on "mindfulness" are trying to capture, though I think that "mindfulness" out of the context of Buddhist ethics and philosophy is really just not as impactful. I heard it from several therapists, but it never really clicked until I started reading Buddhist stuff. I can't call myself a Buddhist, I don't believe in the metaphysics, but studying and practicing Buddhism from a secular perspective has been helpful to me. It's usually very simple concepts, but it is more impactful to me in the ways it's phrased by various Buddhist thinkers and is easier to implement.
It has a lot in common with Stoicism, but gives more tools for dealing with suffering. The ancient Greeks and the Buddhists were actually in contact and influenced each other's philosophies.