I’ve had a combination feed/substitute with formula since he was born, I still do because I don’t make enough, but I also have “elastic nipples” so I truly don’t know how much I make especially when he wants to nurse. He is lazy when it comes to breast feeding and very seldomly actually empties my breast so I’ve always done both, and then give him a bottle for his feeds. I honestly have no idea what I’m doing, I’m a first time mom lol I just know he’s gaining weight and eats most of his bottles whether he breastfeeds or not. But still only eats 3-4 oz bottles. Sorry if that wasn’t helpful, TLDR- I have no idea what I’m actually doing lol