Sorry to hear, going through something similar with my new born. After feeding, burping and changing hw was still fussy. The newborn care center team encouraged me to keep him up right for 20 min or so. It’s helped me. I don’t always have to do it but when he’s fussy. ( like now it helps).
Try after sitting upright for 10-15mins farting them
If you aren’t using a pace feeding position when feeding him I’d suggest doing that as that can help with air intake, eating too fast, reflux and colic. And definitely keep him upright for at least 20 minutes. Both of our kids had mouth ties where we’d have to sit them up in a pace feeding position, burp every .5-1oz, keep them sitting up for 30 minutes as well as do cheek support to reduce milk leaking and air intake (ties were causing all of this) until they got their ties laser revised at around 2-2.5 months and then we didn’t have to do any of that anymore. You could also see if something like Mylicon (gas relief medicine that’s okay for newborns to have) would help.
My little one has been the same, almost the exact same age. I started trying Coleif drops in his bottle and I’ve found that it really helps (a bit better than Infacol because it goes into the milk rather than directly into baby’s mouth - plus I heard that if it IS reflux Infacol can sometimes make it worse). It might be worth a shot if you’ve tried pace feeding, slow teats and sitting them upright for at least 15 mins after a feed xxx
My baby was the same and I struggled through 🫠 when she was around 4 months old the doctor said she had reflux. I’d go to the doctors or try some formula that is for reflux :)
Could it be gas or reflux?