Breastfed Baby Spits Up, Cries, Lots Of Belching Hour Or

Breastfed baby spits up, cries, lots of belching hour or longer after feeding. Even wakes up from gas pain and needs to spit up and burp some more. Baby isn't losing weight but seems to be in a lot of pain after feeding. Poop is always watery. She is one and a half months old.