WTF is with my mind!

Okay so when I wake up from a sound, or a light, or something not just your know normal waking up, I wake up a few seconds before it happens, like I woke up from sleeping tonight due to my desktop shutting down, that was the only sound that I heard or change with in the house that happened that could have woken me up. The thing is that I woke up a few seconds before it made the clicky sound of shutdown. This has happened to me with fire alarms (thank you very much jerks who kept setting it off...) and other things such as cars going by headlights shining in my windows and what not (though never earthquakes due to I am on a water bed and as such would not feel it) but it just keeps getting to me that I wake up and know what woke me up, and then what that thing is happens.

I know I am strange but this just is the weirdest thing for me that I have some way of knowing when something happens that wakes me up before it happens so I wake up to see said event.

If none of this is making sense well sorry.