6 month old with Reflux getting worse

My son was diagnosed with Reflux at a just a few weeks. He started on

Zantac and then went onto Prevacid 2mls 3x/day when the Zantac

seemed to lose effect. For the last month he has been vomiting more and

not gaining weight as well. Two weeks ago he was unable to keep

anything down for a few days and we thought that he may have had a GI

bug that made his reflux worse because he wasnt getting his meds(2/2

throwing them up). He had a good week or so after this where he gained

back his weight and seemed to be doing great, we even tried him on

solids. Saturday, however, he started vomiting again unable to keep

anything down. I dont know if this is reflux, illness or what. Me and my

husband were really looking forward to reflux decreasing at 6 months.

Has anyone experienced this? My son (6 months old and born 5.5 wks

early) is starting to sit and can sit for short periods of time if focused on

something but often falls forward ( which doesnt help the reflux). Also,

we changed medicines on Saturday to the Prilosec liquid. As alot of

people on this forum know it is tought to watch my little guy not gain

weight and be so unhappy. At night he does the back arching, has short

bursts of scream/crying and will not sleep in his crib. He will only sleep if

he is in bed with us. Also, when he is in his crib he will only sleep on his

stomach. All of his symptoms seem to be getting worse as opposed to

better. I would really value any advice, comments etc. We do have a good

dr. and good support but I do not know anyone personally who has had

as tough a time with reflux as my son so the insight would be

appreciated. Thanks