Our bodies, our minds and yes our souls get tired. When we literally have to fight the enemy it wears on all three mentioned above. It has been a practice of many to see how long one can endure pain, agony, and emotional stress. God has wired us to take some of this to a degree, however we require rest, rejuvenation, time out. We are not robots. In the bible you see that endurance is proven by Jesus spending a(40 day) period of fasting in order to prepare Himself for His earthly ministry which was about to begin. It also prepared Him for the time of temptation by the devil in the wilderness. This was an extra ordinary test. Nothing says that we cannot sacrifice for the Lord. But what needs to be remembered is Jesus died on the cross, suffering for us all so that we do not have to. We should not feel shame, or guilt. That through him we are saved. So be at peace and rest. Read the bible. Live life as best you can. Do not let things wear on you. Go to God and leave your burdens. Do not pick them up again.
Psalm 55:22 Give your burdens to the Lord and he will take care of you. He will not permit the Godly to slip and fall.