Hi, I had surgery on an umbilical hernia 8 weeks ago, i have been back to work for 4 weeks. Since returning to work i am always tired by 3 o clock, so much so that when i get home i fall asleep on the sofa until bedtime then manage to sleep all night, 10 hours sleep and i am still shattered. What could this be? I am a 30 year old male, 5 foot 10 inches in height and weigh 13.5 stone .