Handling the moments of profound loss and pain

How do we handle the moments of profound loss and pain? I have been so low before that all I could do is get through one breath at a time and one heartbeat at a time. Sometimes all we have left is to try to make it breath by breath. Have you been there in that surreal space; disoriented — a numb humming, like ringing ears from an explosion, but an explosion of trauma or bad news? Your disbelief simply will not make it go away. Everything seems in slow motion; hope like a tiny speck at the end...