My hemoglobin is 7.7, ferritin 0, iron 16, and iron saturation 4 and just had 2 units of blood. what could this mean?

Anemia: You are still anemic, even after transfusion. Iron levels are still low, implying profound iron deficiency. You did not provide enough information about the reason you became anemic - blood loss such as heavy periods, intestinal bleeding, or trauma. Another cause of iron deficiency may be lack of iron in the diet (vegan) or malabsorption (bypass surgery).