Sometimes you just have to keep going.

Not enjoyment, and not sorrow,
Is our destined end or way;
But to act, that each to-morrow
Find us farther than to-day.
...
Let us, then, be up and doing,
With a heart for any fate;
Still achieving, still pursuing,
Learn to labor and to wait.
-- A Psalm of Life, HENRY WADSWORTH LONGFELLOW