It all started when I had a dream hugging an x friend. I woke up at 1AM to 4 knocks like someone was knocking on the door and it was loud too. My husband was asleep out cold. He is a deep sleeper as am I. And I heard it and then a week later I heard it again at 2AM and last night I heard it at 5:42AM...it woke me up and I was not happy. Can anyone gives me any ideas on what it can be? Or tips?