Your Hb is very low. And as your 25 wks gestation you need to correct it soon as your fetus is in growing phase. Reduce Hb can lead to hypoxia(reduce oxygen
levels) which will hinder the growth of the growing fetus. Iron rich content food would not be enough to get it to normal values. One pint of whole blood will raise ONE Hb%. And as your fetus grows it requires more oxygen and Hb.
It is better to follow your doctor's advice as he is right in his treatment.
wish you good health.