I don’t know what to do 🥺

I try to give my 9 day old baby just 2 oz of milk to see how she does, she always ends up sitting so I take it as a hint to not give her anymore but she still cries for more milk 10 mins later?? And when I give her 3 oz to see how she would do with that she ends up throwing it alllll up- I also try to pause her after every ounce she drinks and burp her but even then she has some sort of spit up what should I do? I’m a first time mom please don’t be mean 😭