Someone once said if you don't know where to begin writing, write about it. Write about the sense of searching, longing. The feeling of reaching into empty space and the feeling of empty space reaching back. The aching awareness of the nothingness in the cavity of your chest and in the slip of space between your skin and your bones.
And perhaps that same reach, that same step from undefinable point A to nonexistent point B, may remind you of something.