First, have you been having a chronic, heavy mensus? If so, this could be the reason. I just got out of the hospital and like you, my blood count was down to 4 and I had to have 8 units of blood due to this. If your mensus has been heavy, you need to see a Gynecologist and have them do an ultrasound on your uterus and have a biopsy. If this isn't the problem, fatigue can be a sign of diabetes, heart problems as well as cancer. See a specialist if you have to, but don't hesitate. There is usually a reason for fatigue. I hope I've helped you.