The job of red blood cells is to carry oxygen and nutrients throughout the body. A CBC, or complete blood count is a blood test used to check your blood count. When you have low red blood cell count you may feel: weak, short of breath, tired, an increase in your heart rate, and dizziness. You doctor can prescribe you medications to help. Some things that you can do is to at a diet with adequate protein and vitamins and drink plenty of non-caffeinated drinks.