Can't Seem to get any Help

I have written on here before about my son and his ongoing issues with what we think it acid reflux. My wife breastfed till 5 1/2 months then switched to bottles as my son would scream being at the breast. Bottles has not been a solution. He only every avgs 24oz a day, sometimes 19, sometimes 27. He is in the 10th percentile for weight and gains very very slow. Because of this doctors aren’t taking me seriously. Over the last week, he got a cold and now is down to 8-12oz a day. This has made his bottle aversion worse and every single feed is a struggle to get anything into him (always has been). I don’t want to wait till he is FTT or risking a feeding tube before something happens but fear that is my only option. He is on prevacid 15mg 2x a day which seems to have little effect. He will suck for a bit and then turn his head away. We have moved to Nutramign three days ago but nothing has really changed. He doesn’t want to eat. He doesn’t cry when eating nor does he vomit. He spits up a lot but is otherwise a happy baby and is developing normally. He is just very small in all likelyhood because he doesn’t eat. I tried to get a refferal to a feeding clinic last week but was refused. I am seeing another pedi tomorrow in hopes things will change. What direction should I take? Should I try another PPI? Should we have tests done (swallow, endoscopy, blood?). Does he need feeding threapy and will it help. Am I staring a feeding tube in the face with no chance of avoiding it. I have no idea what is going on with my son other than he doesn’t like the bottle, didn;t like the breast, and is so so on solids. He has been known to take 7-8 ounce bottles and done so for a few days in a row..however since last wednesday, all of that is a thing of the past. Should I switch back to regular forumla fromt the Nutramign or wait it out to see if it helps. He congestions has been really bad of late so it’s hard from him ot breath. I wonder if the congestion is from the milk. I am just so lost and so worried and want to advocate hard but don’t know what to advocate for?