Can hemoglobin back within 3 days?

Hi, I went to blood bank to donate blood and after checking my blood, they said I have 11.2g/dl of hemoglobin and I can't donate my blood. Plus I just got my menstrual over today. So is it possible for me to recover within 3 days? If I eat seaweed, tuna, kiwi everyday from now. And I don't drink coffee and tea since young and does regular exercises every alternate days.