Growth Spurt? Cluster Feeding?

Hello mummies. My lo is currently 3 weeks old. Recently she has this moment where she would wake up for milk and then after feeding doesn't go back to sleep. And she will keep showing signs of hunger (sticking tongue out multiple times & eating her hand) after feeding, i tot she's still hungry so feed her again however after she drink she will spit out the milk and continue showing signs of hunger and all repeat. Hunger > feed > spit milk > repeat What should I do? Just pat her to sleep if it's not really hunger? Few days ago on sunday she had a moment of what I thought was growth spurt or cluster feed where between 9am to 7pm I feed her almost every 45mins to 1hr apart. However during those moment where she constantly cry for milk (show signs of hunger) after feeding she will vomit milk. And over the span of probably 5hrs she projectile vomit 5 times. She vomited alot literally probably 50-70ml of milk all flew out. And the milk are not fresh which she just drank, but digested. Is there anything we are doing wrong? I always tried to feed her with her head higher up so she can digest properly instead of lying down and we always burp her after every feed and hold her there for extra 5-10mins more before putting her down. Tia for ur advices.