Lowered white blood cell count

Patient: Hi, last week I had a viral kind of fever and I underwent a blood test. everything was normal except the white blood cell count. It is dropped to 2600 and also hemoglobin dropped to 12.3.2 months back, I had regular health check up and there count was 6000 around and hemoglobin 14.2.I feel little weaker. Is it normal? What can I do to increase count level?

Symptoms: Coughing

Doctor: