Be aware of the state of your emotions at all times. If you find
your emotions taking hold of you, breath. Notice your breath and
slow it down. Look up and out at something vast, like the
outdoors. Breath slowly some more. Seeing an actual broad
perspective with your eyes can help your mind make room for your
emotions to spread out thin and evaporate.
A technique since ancient times is pondering God or the vastness
of a deity. In newer times, many people will ponder the
mysteries of Uncertainty at the Quantum level, or imagine their
Actual Size in relation to the vastness of space and the
fullness of Time.
Whatever technique you have at your disposal, make use of it. It
lets you see your problems from great distance away and may help
you unravel them, untangling the knotted Christmas lights in
your mind.