Was there ever any additional blood work done? MCV, MCH, Vit B12, Folic acid, CRP…
As hemoglobin is measured in g/dl it is also depending on plasma volume. So the more water the more “dilution” which means relatively less red blood cells per dl. So there are things like hydration status to consider. And especially, that with lots of endurance training you increase your total blood volume. But your body increases the plasma volume more than the red blood cells. So this means that the blood gets relatively more “diluted”. That’s not a bad thing, but actually good. If you are doing a lot of endurance training that could be the case for you, as your hemoglobin is only slightly below normal values.
There are many reasons for “unusual fatigue”. Maybe it’s even not so “unusual” when you are “extremely active”!?
hope that helps?
and better chew some red meat than the iron pills;-)