Hello, Well you are in your last trimester of your pregnancy and hope you are continuing your antenatal check up and continuing some medicines if not then you have to urgently get an advise of gynecologist as hemoglobin of 6 is serious issue and it can effect on the baby also..  You might need blood transfusion so better soon get an gynecologist advise if needed get admitted for treatment of low hemoglobin. Hope this might be helpful to you.