Both my two had reflux, ds1 threw up for england but wasn't bothered by it at all.
Ds2 screamed the place down, lots of back arching, hardly drinking any milk.
Went to docs - gaviscon - didn't work. Referred to paediatrician at Bupa, he didn't like drugs so prescribed a pharmacy only formula called Enfamil AR (anti-reflux) it's a formula that thickens on contact with stomach acid. It has corn or rice starch added to it.
We could use normal teats because the formula didn't thicken in the bottle.
He was 17 weeks when he saw the paed, we had all the formula on prescription, he stopped when he was 14 months. He would have carried on for longer but I couldn't in all conscience carry on having free formula. He never took to cows milk.
We were advised to wean early with starchy foods so mainly potato, it didn't help so we stopped and he weaned normally at around 5 1/2 months.
Are you breastfeeding? Is this why you have to give it neat? I found with the gaviscon that they say mix X amount to X sized feed but I knew there was no way my son would even drink that amount.
He was having 2-3ozs per feed and feeding about 10-12 times a DAY!!!!! I was exhausted.
We mixed the gaviscon into the formula then divided that down over 2 bottles.
Go back to the docs, you will probably be referred to paediatrician. Don't give up, it is hell trying to feed a screaming baby.