As the others have said, 6 weeks is too soon for your pup to have left mum. Eight weeks would be the minimum i would say.
Food - if your pup is on a dry food then i would definately soak it for the next couple of weeks. Feed it while it is still warm and tasty to encourage her to eat. If she is on meat a splash of warm water on it might also encourage her. I wouldnt worry too much as im sure she will eat when she is ready, she is proberbly a little upset to do so just now. Dont pander to her, place her meal down, leave it for 20 mins then remove it until the next feed (if it is soaked i would bin it and offer a fresh meal at the next feed time). As for water just make sure she has access 24/7 and that she knows where it is.
Oh and of course, congratulations on your new baby
I bought my first JR (well he is supposed to be but i have a feeling he might be a cross) 2 weeks past wednesday and he is a super little chap and we are really enjoying him.
Good luck with your new pup! (does she have a name yet?)
Ang x