Uh, there honestly a lot going on at this age. Not only are they starting to want more than before their digestive system is constantly changing. It could be formula, it could be from drinking more, it could be something in your diet. To help with the spit up make sure you are burping before, during and after feeds. Also try to keep her upright-ish for a little while after a feed.
try a plant based formula or goat milk formula… ik pumping is so exhausting but stick it out mama your so strong and your doing amazing 🫶
My 7 week old is part fed pumped milk and part formula. I don't produce enough to sustain his needs as he's pretty greedy! He gets really farty and spits up but that's normal! I have friends who exclusively breast feed who's babies also fart and puke. Your little one will benefit way more from a happy, non exhausted mama and some formula, than a stressed, tired mum trying to pump all hours of the day. ❤️