How do we not lose our minds completely inbetween losing all we love and afraid of losing others. all we do is survive but even if we sit for a moments peace sorrow, depression, anxiety and insanity set in.
I feel the best way is to keep occupying your self with tasks. Do i need more ammo? How are my barricades holding up? What can i do to make my conditions more comfortable and or colorful? What about my food? Water? How can i get them? How can i get them in dire straights?...and on and on. Then once you are safe (relatively) Let it out. Have a good cry. If you have another survivor, talk to him/her. You need time to decompress. But keeping your mind active should be your top priority. Always be thinking and moving and making your surroundings better.
When people die in the wilderness. They die of guilt. Why didnt i do this? Or why did i do that? or they just give up. Have your cry and vent but then keep going on.
I always keep one ear bud in my ear the music keeps me going. If you don't have this luxury then keep books and things of the sort as well as keeping a journal and a notebook of where you have been. If you have the ability try to leave notes when you travel you may help some one else.
I have to agree with Kyle to an extent. When you're on the move or in the open you have to stay focused, or you will end up dead. But once you find yourself in a fortification of some kind, preferably with a sizable group of fellow survivors, I'd have to say music.
After all, the minstrels and bards of the dark ages and early medieval period were more or less nomads who wandered the land expressing themselves in song just to stay sane.
And folk music was born of just this kind of scenario: A group of travelers with little or no relation to one another fending off death from every conceivable direction.
It may sound terribly hippie right now, but it makes sense when the chips are down and the zombies are lurking just outside your fort. Find some acoustic guitars and have yourselves some circle time. You'll all feel better in the end, and more importantly, I'm sure you'll find that you work better as a team when that next emergency comes 'round.