I second the silent reflux. DD had this and still suffers from it now, just not as bad as she used to! We used the gaviscon infant sachets as well as a formula for reflux. We also were on losec until 4.5months old and I added infants friend to every bottle. It seems a lot but it helped massively. They don't have to be losing weight to be suffering!

If he does feed, I suggest you kept him upright for about 30minutes after so gravity can help.

Hugs hun. It's not easy. Your a good mummy and doing all u can. Keep it up xx