Why Hemoglobin Goes Down After Valve Replacement Operation Why Do I Feel So Tired After Taking Iron Tablets?

Why do I feel so tired after taking iron tablets? - why hemoglobin goes down after valve replacement operation

I was recently diagnosed with anemia, hemoglobin of my 10 was and gave a course of iron tablets to take. I have about a week and I now feel more energy than before, in fact, I feel more tired than usual and often have to lie back just a little energy. So my poo was hard and black, which is not very pleasant.

Is this normal or should it feel better already?