[Messie]

Trying to get to sleep earlier than normal is nigh on impossible. You are trying to put your 24 hour circadian rhythm into phase advance, which all sorts of studies have shown, doesn't suit us at all. If you need to change your shift or getting up time it is always better to go for the phase advance system, where you have to stay up longer before you get some sleep. This works with our natural inclination to stretch to a 25 hour day.

Also worrying about it is a surefire way to prevent sleep. As KellyJo said keep reminding yourself that your body can cope with little or no sleep so you will be fine for a few days. Studies of sleep deprivation have shown that we can go for days without sleep and still be ok'ish.