There is this knocking in the wall   

I sleep my head next to a wall which works as a separator between another room's closet. There is not much too it apart from an occasional knocking sound, it is a quick sequence of 2 taps and occasionally 3 taps. Being echoish more than a knocking sound should be, I believe it is coming from inside the wall. Normal house phenomena, right?
I have a laptop using which I am typing right now. When it is in sleep mode, it makes this really irritating high pitch noise that drives me crazy so I completely cut the power and unplug it so it doesn't make any sounds - and it does not.
Yesterday morning something strange happened; I went to sleep really late, at 3ish AM. Then the usual nightly event came in - the knocking.
I never made ANY deal out of it but this time, for some reason it creeped me out. It was a lot more persistent than it ever was and then my laptop randomly turned itself on (the power from it was cut and I killed the system).
Now the last part I wouldn't be surprised if it were hallucinations but I was like seeing the darkness crawl away into the darkest corner. It was a really strange sight, by crawling away I mean it didn't go away instantly but more progressively and slowly.
Maybe I am grabbing at straws here but you never know.