The seven minute morning trap!

When I wake in the morning, it is almost invariably seven minutes before my alarm clock is due to blast its stunning klaxon over my sleep fogged head. Naturally, to spare myself the torment, I turn of the alarm, (after all - I'm awake now aren't I?) forgetting in my semi-comatose state that this is the same old trap! Within moments I have sunk gently back into the duvet, sleep enfolding me as I sigh gently - only to wake panicking, exactly thirty seven minutes later! Once again I am just in time to be ten minutes late for work!

I have tried setting my alarm just ten minutes earlier, with little effect other than to find myself waking just that little bit earlier. An hours difference just means that after turning off my alarm I sleep for an hour...

Is this a phenomenon others have experienced or am I in the grip of some unique malignant force, determined to destroy my sleep patterns and my career?