Baby with severe GERD & possible other problems... can someone help

Hi there

I have a 6 and a half month old baby who has always suffered problems feeding & extreme trapped (burp wind problems)

General symtons

severe back arching & screams whilst doing so, arching more severe during/after feeds, resists winding as if painful,
throws himself backwards & goes rigid, lots of sickness during feeds, extremely windy, reflux episodes clear acidic sickness, wet burps, irregular bowel movements, when bowls move pushes & grunts very painful looking.
very unsettled during & after feeding.

feeding takes around an hour for 7xounces as needs winding every ounce & still has excessive wind. Still has wind hours after feeding & wakes up with high pitched sqeeling as if in pain.
Resists winding during feeds & screams, arching.
extremely difficult to get wind up during feeds.

my son has now started losing weight due to the sickness, he has been referred to a paedtrician & in the meantime has been put on omeprazole 8mg 1x per day - but im scared to give him it. I think he has GERD but also perhaps an underlying condition making him empty his bowls not very efficiently.

i have read re Joepathy can anyone please advise me treatment for my son. Is there anything that i can use for gerd, sickness & wind or everything described above.
i have read about nat phos#6 would this work?
Im so scared his esphohagus is imflammed already causing so much pain would this help it?

Please note mikey has porridge after his milk (pure oats) and now lunch trying to reduce sickness/help his weight im not sure if meds would need to be given after both food & milk?

Thanks so much
heather