Perspective becomes easier when you remember how small your moment is inside a very old world.

Set your current situation against the age of the ground you are standing on and it does not become unimportant, it just stops being the center of everything. The world was fine before this and will be after, which is oddly steadying rather than diminishing.

When something has taken over your whole mind, try widening the frame deliberately. A hundred years, a thousand. Not to dismiss what you feel, only to loosen its grip enough that you can think about it instead of just being inside it.