Hi there...this is Dr Harsha from bangalore answering your question...It may be due to telogen effluvium,androgenic alopecia,thyroid disorders,hormonal imbalance.... Kindly consult the dermatologist for the perfect diagnosis and proper treatment....I would advice you to take biotin supplements once daily and to avoid stressful life as much as possible..try doing yoga and meditation...do not wash your hair roughly it should be very gentle...as I told earlier consult nearest dermatologist for clinical examination they will help you.