I have a three week old baby boy who I am breast feeding with the help of breast shields, I wouldn't be able to do it other wise. I have been advised by my Health Visitor to wait until he is four weeks old until I can express milk? and need some advice. I have no storage bags to freeze the milk into, can I use Avent or Tommee Tippee bottles? Also, how much milk from each breast should I expect to get on my first attempt? I have visions of filling the bottle and don't want to be disappointed. Many thanks.