You'll have that fatigue for a while. I was exhausted for two months, though some energy came back around week 6. Even then, if I did anything - even just make a run to the bank (driving) or spend some time with the family on weekends - I would need to take a nap. At around two months, I had more energy... but I will say I did not return to "normal" until around three months. I still take the occasional nap, but because I feel a little tired, as opposed to drop dead exhausted. Since I am low-energy anyway, I might be feeling normal where a high-energy person would not.