Could my 3 1/2 month pld have acid reflux or GERD?

Hello, my name is Sandeepa. I stumbled across this forum while doing an internet search about why babies would suddenly stop eating. I'd like to briefly share my story, as it resonates so much with the others I've read on here.

My son, now 3 1/2 months old, suddenly stopped taking his bottle about 2 weeks ago. At first he would take about 2 ounces and then begin making gagging sounds, so I would take the bottle out, burp him, give him some time to regroup, and then continue the feed.  Lately however, he has been completely refusing the bottle. The minute I put it into his mouth he pushes it out, turns his head from side to side and begins to cry. A little background info: my son was born in a birthing center and had severe jaundice which went undiagnosed by the midwife for almost three days. When we took him to the pedi, she said he needed to be hospitalized ASAP because he had dropped more than a pound from his birth weight in only four days and his billirubin level was way too high. She suggested I continue breast feeding but supplement with formula because she didn't think I was making enough milk. Long story short, we avoided hospitalization by nursing and supplementing around the clock for 72 hours in a row and eventually his weight came up and billirubin came down.  However, our new dilema was that he developed nipple confusion and refused to nurse. We got a lactation consultant involved who was of very little help. Finally I decided to pump and feed him my milk via a bottle.  This arrangement worked fine up until a few weeks ago when my son's strange behavior started.  He began mildly the vehemently refusing the bottle. I would have to spend over an hour trying to feed him, which cut into my pumping time for the next feed. I didn't have time to nourish myself (a nursing mom needs to consume 500 extra calories and I couldn't even eat or drink a "regular" amount of food to get basic calories) because all my time and energy would be spent trying to feed my baby and take care of his 4 year old brother (whom I'd have to drop off and pick up from school). When my husband and I took our baby to his pedi, she suggested changing the bottle/nipple, when that didn't work, changing the formula...I'm sure most of you know the drill. When this didn't work, she said maybe he's teething or has bad congestion or gas. We bought whatever OTC meds/soothing agents she suggested and tried everything to no avail. We sought a second opinion and again were told "He will eat when he's hungry, just space out his feedings more." My baby happily went eight hours without drinking his milk and didn't cry for it once.  He gladly took a pacifier but not his milk bottle. I have resorted to feeding him in a partially sleeping state. This doesn't always work because sometimes when he falls asleep he stops sucking and I cannot get him to finish his bottle. I also have to let him have his pacifier and then do the switcheroo with the bottle when he starts falling asleep. With a great deal of struggle we're somehow getting 24 ounces into him every 24 hours, but this is not nearly enough for him to gain weight. Before this problem started he was comfortably taking up to 30 ounces a day and gaining anywhere from 6 to 8 ounces a week. Now his weight has remained pretty much the same for two weeks so we are staying afloat for now but he's not gaining which worries me very much. I'm at my wit's end and just cry every day. I feel like nobody is listening to me. When this all started I felt like there was something wrong with my baby and nobody believed me. "It's just a phase...babies sometimes go on feeding strikes, he'll be o.k.", I was constantly told.