“If the ax is dull, and one does not sharpen the edge, then he must use more strength; but wisdom brings success.”
I’ve encountered similar problems in the past. The less prepared something is for its work, the harder it is to accomplish its work.
A dull ax requires more physical energy to cut through a tree. A violin bow without rosin requires more physical strength to pull a sound out of a string. A tired mind takes longer to digest information.