I've been expressing some milk to store in the freezer. But my hv said to start using last months milk as the milk changes to babys needs. She is almost 6 weeks. It was 2oz and she drank an oz and it gave her wind. But I found before the wind I felt really sad when she fed and when she took a break I desperately wanted to put her back on the breast. So as soon as she winded I didn't offer her any more bottle and breastfed instead. I found myself worrying she'd reject me as she drank the oz really quickly. I'm really surprised at how sad I felt. My sin was ff and I was always fine with bottles.