Ferrum phos 6x will never increase your haemoglobin. You will have to take iron supplements. Ferrum phos will help you to absorb the supplement properly. It may also help you with the side effects of iron supplements like constipation.
So twice a day or 4 times a day of ferrum phos won't make lot of difference.
Do serum ferritin levels. Those indicate the amount of iron stores in the body. If they are good, you don't need iron supplements.
Then you will need homeopathic constitutional medicine that will help you form good amount of hemoglobin.
You should also investigate the other causes of anemia. Other causes may be nutritional, b12 deficient, folic acid deficiency, or excess blood loss, or hemolytic anemia, etc.