Suggest you have blood work done to find out if your Vitamin B12 levels have decreased or not.
To have healthy bone marrow is to keep your white (immune system) and red blood cells healthy by eating healthy. Eating the proper fruits, vegetables, carbohydrates, proteins and moderate fats daily.
Suggest going to your MD and get blood work done to see if you have any mineral or vitamin deficiencies that maybe causing the fatigue.
Suggest going to a doctor and get blood work done to find out if your vitamin levels have decreased.