3w old eating too much?

M • 💍🐶👶🏽🎀👨‍👩‍👧💕
My baby can literally down an entire 6oz bottle of breast milk and still act like she's hungry afterwards. I've tried giving her a pack, but she'll spit it own and clad team until she has a bottle and falls asleep. 
Shes barely 3 weeks old, but almost never spits up the milk. She just gets really gassy. I'm not sure what to do. 😕