do you have a forceful let down? If you do, thats the root of all your problems. His poops should be yellow and seedy like dijon mustard. If they are stringy, green, mucousy and look like wet lettuce, he's getting too much foremilk, which will make him spit up, cranky, gassy, and very uncomfortable.
A newborn shouldn't be drinking 5oz! Get him back on the breast, see a lactation consultant if you are having problems latching. Let him latch, and when your milk lets down, unlatch him and catch the spray into a towel. When the major spray slows or stops, let him relatch and nurse until he's done on one breast. Don't unlatch and switch breasts, its not necessary, he needs to nurse one breast per feeding so he gets the hindmilk. He can't grow and thrive unless he gets hindmilk. You are very engorged right now so you may have to nurse ihm on one breast for 2-3 feedings in a row to ensure he gets really good hindmilk. But don't switch breasts, one breast per feeding, and unlatching during letdown until your milk productions evens out a little.
Please find a lactation consultant to help you. He's not having a problem with your breastmilk, its just letdown or not gettign enough hindmilk/too much foremilk.