Hi, thanks for using healthcare magic
Excess fatigue can be related to anemia, infections, heart disease
because of decreased energy, hormonal
abnormalities such as a low thyroid levels, depression
, side effect of medication or a sleep disorder
The iron would be needed if you have iron deficiency anemia
which would be diagnosed with a full blood count.
You may want to consider visiting your general doctor first who will first take comprehensive history to determine any additional symptoms that may point to a specific cause.This may include screening questions for sleep disorders or any psychological problems like depression. This would be followed by examination and investigations such as the full blood count mentioned.
If your doctor thinks that you need to see a sleep specialist, he or she will refer you.
I hope this helps