You work so hard, but somehow it is just not satisfying. God knows, you may be fishing from the wrong side of the boat.

John 21:5-6
Then Jesus said to them, “Children, have you any food?”They answered Him, “No.”
And He said to them, “Cast the net on the right side of the boat, and you will find some.” So they cast, and now they were not able to draw it in because of the multitude of fish.
http://www.biblegateway.com/passage/?search=john21:5-6&version=NKJV