Rental lease break

We are breaking a 2 year lease (3 month remaining) and the realestate has already signed a new tenant before we even vacate. They have increased the rent. It was advertised for around $15 more than currently paying.

The realestate has a week break between us leaving and letting the new tenant move in. They are expecting us to pay rent for this period, is this normal? How is it lost rent if they signed a contract already?. There is no damage to the property and it will have a professional bond clean done.