formula

my 3 week old refuses to eat any less than 4 oz ever 2 hours. I'm pretty sure this is to much. Even her pediatrician said this is to much and that I need to stop feeding her so much. But if I give her a pacy she just spits it out and starts screaming bloody murder, the same if I only give her 2 oz. she also spits out the bottle a hundred times, I've triedb 30 different kinds of bottles, she refuses to latch on to breast feed also. My sanity is pretty much non existent right now. I can't do the constant screaming. what do I do?! How can I keep myself calm?!