I'm sorry this is such a scary time for you.
My DD was born at 35 weeks and 1 day. She spent 2 weeks in the NICU, and when we brought her home, we heard nothing from the NICU about GERD/reflux, or whatever was going on, and we were new parents, so we were clueless.
Finally ended up taking her to the ER on the 4th of July weekend, waited until around 3am to be seen, and it was determined there she had GERD. Her pediatrician never completely diagnosed her w/GERD; he was hesitant, but I will say it all cleared up by probably 6-7 (8?)months.
We had some really scary times, too. And in the beginning, when your hormones have yet to settle, and you're so sleep deprived (and you have other little ones)...we had no family support (I'll spare you the drama of that), we were new to the neighborhood so we knew no one...I remember one time in the middle of the night, DH and I whisked our DD out of her car seat gagging, turned her upside down, we were trying everything, and I just lost it. Fell on the floor, crying myself and DH was like, "honey, you have to pull it together at least until we help DD". It was just too much. Our pediatrician later advised me that the baby senses our stress, so as I was more relaxed in the future about episodes, I think it helped our DD get through them as well.
One thing that helped us is that our DD slept in her carseat 100% of the time for the first 4, possibly 5 months of her life. This helped with the GERD/reflux, or whatever it was that she had. We also added something to her bottles...think it may have been "Milk of Mylanta". Every one. That helped keeping things down.
I remember for so long her sleeping in her carseat at my bedside, and me only sleeping lightly so I could keep an ear out to hear if she was having trouble breathing. I'd keep a small, reading flashlight in reach so I could flick it on at any time to see how she was looking without having to turn on a brighter light.
We also kept those nose suction thingies around, so we could suction the gunk out from time to time if flipping her over and upside down didn't do the trick. Our pediatrician told us not to jam it down her throat, but to put it to the inside of her cheek and suction. That helped sometimes as well.
We almost hooked her up to an apnea monitor, but by that time, the sleeping in her carseat, the additions to her bottle...it all was starting to slowly get better.
Good luck to you. I promise it gets better at some point.
~Sandy/DD born via emergency C at 35 wks/1 day June '03 due to Severe PE/class III HELLP
CAUGHT THE EGG!! Estimated hatch date: 3/13/05; scheduled C at 39 weeks...or earlier if needed.