Help!! Newborn not pooping

Hi all can anyone give me some advice, my baby girl is just over a week old and isn't pooing as often as I think she should. She goes two full days before doing a poo and then cries when she finally passes quite a lot. It's soft and yellow but surely she should be going more often?? FTM so not sure what to expect. The longer she goes without a poo the less she drinks of her milk also struggling to bring up wind. Can anyone shed some light on this for me?should I be as worried as I am?