Much of what feels like being extremely tired comes from discouragement because of circumstances and natural conditions. Encourage yourself in Me--in spiritual truth--and take the time to be rejuvenated, says the Lord.
1 Samuel 30:6 And David was greatly distressed; for the people spake of stoning him, because the soul of all the people was grieved, every man for his sons and for his daughters: but David encouraged himself in the LORD his God.