Backbreaking

As I close my eyes to rest,
the past flashes through my head.
So many times, I've come so close,
by all rights, I should be dead.

My every day seems like a test,
to see how much more I can take.
But, they just keep adding more, and more,
how much longer until I break?

How much can one person stand?
How much longer until I crack?
Will it take just one last strand,
or will you have to add another stack?