He could be going through a growth spurt. Both our girls eat like there's no tomorrow when they go through growth spurts, and would scream like there's no tomorrow unitl they got fed...and like the pediatrician said, he'll quit eating when he's full. I remember with my oldest, I had just given her a bottle, and about 10 minutes later, she started screaming. I couldn't figure out why...changed her diaper, changed her clothes, she didn't have a temp...couldn't figure out what was going on - called the pediatrician, they said, "Feed her." After arguing with them for about 5 minutes, they again said, "Feed her." I finally did, and she settled right down - and hoovered the bottle down. So - let him eat.
Meanwhile, I would do 2 things.
1) Put a couple spoonfuls of cereal in his bottle right before bedtime or naptime. We call that "slipping them a mickey".
2) Put 2 squirts of Mylicon in the bottle too. When our daughters hit the 3-6 months mark, they started to get gassy. 2 squirts of gas relief drops (a.k.a. Mylicon) worked WONDERS for us.
For what it's worth - and good luck!