Steffy and Soph - have you considered lactose intolerance? My nephew you had it bad, but he would still drink the milk and want more, in an attempt to comfort his poorly tummy. He didn't really throw it back up, or didn't do so often. He ended up on special formula on prescription.
Randomly 3 weeks ago Zac started the same - awful screaming after a bottle, but still wanted to drink it and then he pooed in every nappy, 8 in a day and they were jelly like. I was beside myself, spoke to HV and she said perhaps it's the lactose so told me to swap him to Comfort Formula as it's easier to digest, has less lactose/milk protein and helps with colic/constipation. The first time I gave it to him he happily supped 6 ounces, whereas before he only drank 3/4 ounces at best. I do have to give him cooled boiled water as it's quite thick stuff but he's much better.
Perhaps something to consider or discuss, if reflux doesn't seem the issue....?