GERD vs GASTRITIS

After searching for Gastritis symptoms I found out that some of the symptoms matched my condition like :-
-Nausea; Vomiting
-Rapid heartbeats, sweating, fever, loss of apetite
-Burning sensation in the abdomen area..
and much more but in my case I was getting these symptoms in the form of episodes(Like once per month or week) and with further more research I found out about choronic Gastritis after an Endoscopy I was dignosied with"Mild Antral Gastritis"

My question is I also have GERD but is the nausea coming from the GERD side or the Gastritis side ?

Im getting a Lap.nissen fundoplication for the GERD this week but is it going to affect the Gastritis like make it better or worst ?