You know what a knee-jerk reaction is.
In the clinic, the doctor taps your patella with a hammer and your brain bypasses neurons producing impulses in the hamstrings that involuntarily raise your leg.
Likewise, there are social "hammers" which get reactions out of us. Also called "button pushers", these external stimuli can get us worked up.
The good news is that we are equipped with the ability to pause before we react. Philosophers say that this pause is where our freedom resides.
A quick review: to react is to be impulsive and unthinking; to respond is to be conscious and intentional.
One way to respond rather than react is to name what you are feeling. When something happens that is hard for you to handle, try to say what is happening: for instance, I feel tightness in my chest, I feel anxiety in my throat or I feel anger in my heart.
Does it take away the feeling? Perhaps not right away, but it will eventually lead you to a place of peace which will become more familiar to you- and a better place than being on edge, feeling tightness, anxiety or anger.
In moments of utter craziness, intense darkness or just wordless absurdity, let your inner friend say to you, "You won't always feel the way you are feeling right now." Take comfort from this and trust this friend. It's one of the best parts of you.