Hoping you feel a little better by now, if you are still reading this.
Make sure you get saliva cortisol and hormones testing done by a naturopath. It will identify a lot of fatigue related issues, as cortisol is essential. It can help show your adrenal function.
Thyroid tests are essential too. Remember most doctors wont run the full lot, and only a few thyroid tests. They will also interpret the reference ranges differently to what a good naturopath will.
Remember, a "normal reference range" may not be normal for each individual, as we all have different bodies functioning at different levels with different needs.
Vitamin D tests, the level needs to be at the upper end, so read up on vitamin d and the immune system and how important it is for our daily functioning.
Iron levels need to be tested.
Many CFS/ME patients and sufferers end up testing for lyme and many get positive results. So if all the above tests come back well or are being treated, then lyme is another avenue of testing. Usually expensive, so the above options are cheaper and easier to begin with.