Amyone else experienced this.
Last night I had an episode which presented as a loud buzzing sound
I felt that I had to wake myself up, I tried moving and vocalising, neither worked, so I threw the duvet off of myself.
That woke me up, and the buzzing stopped.
It is an odd sensation knowing I am in a state of sleep and need to wake up.
Can be scary, but I get these occasionally and am used to it now.
Isn't that sleep paralysis? I've experienced that many times myself, although it was when I was much younger, teens to twenties I reckon. It's quite common. Google it. 
Although, I will admit it's very unnerving.
Just realised what Mustard Tree called it. Exploding head syndrome! Sounds horrible haha.
I have woken once in my life when i had that feeling when they say your half awake and half asleep but your paralized and you cannot move. Bit frightening but its never happened again. No buzzing noise though.
