Are you drinking enough water? And I don't mean "LL says drink 2ltrs so I drink 2ltrs", I mean are you drinking the water that YOU need?
I know that if I don't have at least 3ltrs a day, I feel achey tired and my stomach feels different to normal (well, normal for LL anyway!)
Never underestimate the power of a glass of water to whisk away feeling 'hungry' very quickly!
Also, don't confuse feeling 'empty' with feeling hungry.
For the duration of this diet you are going to feel very 'empty' in your stomach (obviously!) - you'll learn to love it, honestly!
As Sean said, it could also be that you are simply missing eating something, it's still really early days for you yet and no doubt your body is still adapting to what is happening to it.
But try not to worry so much, Rachiie, and icemoose said it spot on, if you are sticking to LL, you HAVE to lose weight, it is impossible not to.
So just try and enjoy it

x