My nephew, who is now 23, had something similar happen to him. He would actually power puke across the room, stiffen up when crying & cried all the time. My sister kept insisting something was wrong, they kept acting as if she were over reacting. Finally at 4 months old the doctor saw first hand his puking skills and had him tested. Turned out that where the esphogus meets the stomach there was a hole, where that had not completely closed. He said it was not uncommon and unless Taylor was failing to thrive he would outgrow it w/in a year. The boy was 2 weeks premature and weight 9.4 pounds. He was huge. SO...they had to strap him in his crib at night and lay him on on inclined foam rubber. As long as they didn't lay him down flat after eating he was fine.
He drank Donogel (think that's right) for a long time because of the acid reflux. And had a very sensitive gag reflex, but he outgrew it and never required surgery.
SO I say all that to say, you're doctor probably is right. You can always approach him with questions about possible seizures, but honey the internet can be a hard place to navigate when looking for medical help. We can almost match our symptoms to all manner of deadly disease/conditions. I would listen to your doctor, he has seen her in person and knows what he is doing. If she continues, then talk to him about your research, but as she was in the hospital, I would feel confident that had she'd been having seizures, they would've caught that.
Best of luck to you, it's hard when our babies are sick.