You have not given details about yourself like age, gender, outdoor or indoor work, your diet, complete list of medication using, family history of hair fall, pattern of hair fall, any other concurrent diseases etc. Please provide this. Have you consult dermatologist? If not then, consult. Regarding hair fall, it requires treatment as per cause. According to your doctor your scalp is healthy, so there shouldn t be any infective cause. May not be the Autoimmune cause as well. Most probably you have androgenic alopecia, which requires some lotion over scalp like minoxidil along with some tablets. These are somewhat effective and decreases hair fall but not cure the disease. General measure are also important that may include covering your hair while traveling, shampooing hair with medicated shampoos once weekly, maintaining cleanliness of scalp, avoiding junk food, taking good diet, stopping overthinking about your condition etc.