3 years ago, i was sleeping then when i i was suddenly awake by the knock on the my door. so i suddenly stand up, at that point i felt dizzy and a blackout , and a humming sound. after a couple of minutes dizzeness was gone and my eyes return to normal sight but the humming sound never stop until now , i still hera it. it desturbes now my thingking, my mind. my doctor have found nothing. is anyone experience this? i need an advice please..