bigs hugs and sympathy, been there, done that, got the puke-covered t-shirt.....
my lo has had reflux really bad too and is nearly four months old too. I started with just a bedtime routine because I wouldn't know what he would throw up and whaich meals would stay put.
Thankfully with medication it has eased but I found it worked best for my ds that if he did throw up to try feeding an hour or so later when he would be getting peckish again but not so hungry that he made a total piglet of himself. It ended up becoming our own version of easy in that it was eat, throw up, east an hour later, play/activity, sleep then eat again. I found it difficult to stick to set times but figured as long as he was keeping food down and knew what came next he wasn't too bothered about times either.
As his meds have kicked in it has been easier to slowly bring him onto 4hr easy but it has taken a lot of time. The only thing that is structured is bedtime, with a bath, dressing in pyjamas and a feed in the darkened nursery before bed so he knows that's his "big sleep". He's now teething (the first two little beasties appeared this morning....finally!) but normally he will sleep 11 hours and is becoming a lot more settled.
Please persevere, it does pass, honestly.
Big Big Hugs