Freeze, its because your body doesnt care what time the clock says. If its used to going to sleep at a certain time, and waking up at a certain time, then that's what it wants to continue doing. Last week, I was waking up 10 min before my alarm went off, just before 7am. This week, due to the clock moving forward, if I was to let myself wake up naturally, I'd be waking up just before 8am. So im back being reliant on an alarm, and I dont like that. I know my body clock will adjust, but its annoying waiting for that to happen.