She’s constantly hungry because breastmilk digest very very quick that’s why it seems like she’s always hungry.
Spitting up milk is normal because their stomach is so small. And their digestive system are not fully matured yet to contain them so on occasions they tend to spit up milk. Lastly, did u warm the breastmilk alittle before giving her? So u pump it out and give it in a bottle or latch?
Dayana Azhar