I also think 8 weeks is rather long. I had a fortnight after when I was more often asleep than awake and looked interestingly pale! But I did start to pick up then, but would say that at the end of a month, I was more or less back to normal.
I think it varies from person to person. But I think 8 weeks is an extended amount of time to be feeling tired and fatigued. Except for a limp, I felt near 100% within 2 weeks. I was near 60 at the time.