Help!!!! 9 week old has reflux

Lexie

We were told when she was a week old she had reflux but because she was gaining weight (formula) and wasn’t constantly fussy doctor wouldn’t prescribe anything for her which we were okay with. Fast forward she’s nine weeks old and we were told at her 2 month appointment that it was going to get worse. Within the last week she’s began gaging sometimes acts like she’s choking after she eats, arches her back cries cause of the pain but doesn’t spit up hardly at all. This all used to happen just on occasion. She’s gone from eating 4.5-5 oz every 4 hours to 3.5 oz every 3 hours. She sleeps through the night. We have her in a rock in play, she’s always up right (30 mins after even if she needs changed) with the expectation of diaper changes, is on a gentle formula and we use advent anti colic, gas reflux bottles. She’s been going to a pediatric chiropractor for about 5 weeks now and that did help in the beginning but now I can tell it causing her so much pain and with the frequency of the reflux now I just don’t know what else to do? Are there other things I can try? Do I take her back to the doctor? I know it could be much worse but I hate seeing her in so much pain 😔 any advice/input would be much appreciated.