Hia nightelf, The best thing you can do that I know of, is to find a CFS support group in your area by doing a Search on Google or some Search engine that you use.
Once you contact someone from there, you can ask if there are any CFS Dr.s in your area and let them work with you to determine what is wrong with you.
A good CFS Dr. is one of the best most of the time, because they know what other illnesses can mimick CFS.
They usually very thorough also. You can contact someone at www.cfids.org
and ask for a Support Group connection in your area.
Whenever we get this fatigue, until we're diagnosed, it is easy to imagine all sorts of things.
I also thought I must have had brain cancer because of the pressure in my head and cognitive impairment it caused.
That website will give you the symptom list that you can check against what you're feeling.
Fatigue is just the main one. Others symptoms would go with it.
Wishing you all the best.
LateNeuroLyme + CFIDS = Lord knows what.
Romans 8:28 ~ And we know that ALL things work together for the Good, Y
for them that Love God, for them who are the called according to His purpose.