Update...

So I did a blood test this week and found that I was extremely low in Vitamin D. I used to live in Australia (Perth) for several years before moving to Netherlands 1.5 years ago. I guess my body got accustomed to the abundant sunlight and my Vitamin D levels has been slowly depleting since moving to Europe.

The initial fever may have been a trigger that really exposed the symptoms of the Vitamin D deficiency. That's perhaps why I haven't recovered fully in over 2 months?

I see Vitamin D deficiency can lead to many things include fatigue, weak immune system, depression, and trouble sleeping (also could be effect of depression).

Could this explain the whole situation? If this is indeed the answer than it is a lot better than post having viral fatigue.

An Indian girl at work had the same problem. After 1.5 years in the Netherlands she started getting a lot of fatigue, depression, hair falling out etc... Turns out she also had Vitamin D deficiency.