Maybe if someone else lives in the house they were playing a joke on you (crazy idea, but someone might just try it)
I know its not uncommon for people to wake in the night and say they heard something, so if the above isnt possible, then maybe you just woke from a dream. I know you dont like the sound of that possibility, but thats what i tell myself when i wake in the night because i heard noises that have no reason to have been heard. Otherwise i would never sleep again.