i can understand why DD is having trouble with it. She wants mummy to be there for her after school as she's used to it.

I think you need to explain to her the situation, that its best for the family and for you that you work.

More money = more freedom to spend money on things which may have been considered as luxurious in the past.

working mummy = happy mummy = happy family. For your sanity, not that you didn't enjoy being home for the kids, but they are all now older and don't need you as much as they did previously. Tell DD that you enjoy working.

I'm sure they'll understand, it's probably just new for them and need time adjusting to the routine.