Low volume eating, not getting better

I am new here and am just wondering if anyone has any thoughts (or experiences to provide hope). My baby is 11 weeks old, born at 57% for weight down to 11-15% pretty quickly by 2-3 weeks old. She is on prevacid 5mg bid and zantac 0.6 ml once a day. She was diagnosed with reflux and also milk intolerance and is on neocate. On neocate she has stopped the projectile vomiting (also had an ultrasound which was negative) but I am concerned because she only eats about 20 oz a day. She weighed 9 lb 7 oz last week (up 4 oz from a weight check 9 days prior). We are concentrating her calories (new just since last weeks weight check) and I hope that will help because seriously I can’t get her to take more than 2, maybe 3 (once or twice a day if that) at a time. She takes 2 oz pretty easily but then turns her head, bats the bottle away or juts out her tongue. The arching and crying we saw in the beginning with a lot of feeds is much better. She definitely still spits up (with no crying or fuss) especially if she goes in a bouncy seat or carseat too soon after a feed. Occasionally it comes out her nose and that is the only time I really get any crying or arching. also, she eats about every 3 hours when I force her to. If I let her demand feed, I can’t imagine how little she would eat. Otherwise though, a happy baby- smiling, cooing, holds up her head, would sleep through the night if I didn’t wake her to feed.