Nausea after taking nausea injection.

I have been suffering from severe gastric and acid reflux, I went to a doctor and he gave me ondansetron 2mg injection for 4 days but not continuously , but within 6 days, but after I started taking this injection I noticed one thing, I started feeling more nausea , I started vomiting , after taking it for 4 days I stopped it because I didn't feel OK, nausea had increased, after stopping it, nausea became worst, i felt like vomiting but could not vomit,  I started burping allot , like for every second I am burping , my throat started to hurt because of that, I never had such problem even though I have gastritis , this burping is so bad that I can't even eat and talk and sleep , so I again went to doctor and he gave me Periset 2mg and this burping stopped after like 8 hours, but I am sure that it is going to come back , please help me what should I do ?