I've never bothered to explain this feeling to anyone as it's not easy and I wouldn't expect anyone to understand. It doesn't happen as much as it did when I was a kid but I just had one tonight. It's only ever happened when I'm lying in bed and I can always make it stop when I want by talking out loud. I don't know what it is but it doesn't worry me. I've considered every possibility mentioned in these posts from an anxiety attack to some kind of superhuman heightening of my senses. It's such a relief knowing that other people get this. I feel it's important to keep this forum going and maybe one day we'll get an answer.