Hello, Welcome to health care magic. Sudden and severe hair loss is called telogen effluvium. It is a hair loss pattern usually triggered by a physical illness (like viral fever, typhoid fever, hepatitis, etc), stress, crash dieting, weight loss, child birth and surgery which you would have about 3 - 6 months prior to onset of hair fall. It could also be due to underlying anaemia and thyroid abnormalities. You need to check your hemoglobin levels, serum ferritin levels and thyroid status. Please have a good diet including green leafy vegetables, eggs, dates,etc You could also take supplements containing biotin 5 mg. Hope this helps. Take care.