Feeding strike

[Evilwater]

I need help! My son has gone from 30oz of FF to 20oz a day at a push. He is 4 months, sleeps well but is VERY grumpy during the day. I offer the bottle any time he crys/ whimpers and he just won't drink, I've managed to get some milk into him but its while he is laying flat.

He suffers from colic alot, and it's battle each day, which is why feeding while he is flat is bad. I've used infacol, and gripe water, as well as massage and different types of winding, for the colic and it has only lessened it a little.

I just don't know what else to do now,
Evil