Hi Sanna,
I'm sorry about your little one....my son is now 7. He was diagnosed with GERD when he was just over the age of 2 but we're sure he had it since birth, it just took us a while to realize his doc was an idiot.
Many infants outgrow their reflux by age 1 year. Thats because their LES valve gets stronger by then and it doesnt open up to allow food and acid to go back up the esophagus. Most Ped GIs will give a couple of trial runs - stopping their reflux medicine for a few weeks to see how things go around age 9 months and 12 months. If symptoms return - wet burps during a meal, vomiting, arching the back, crying and/or eating less they'll continue the meds.
I hope your little one outgrows it!