If you had GERD serious enough to end up in a ER you need to first make an appointment with your physician to determine a proper course of action or if you have ulcers. He might refer you to a Gastro doctor if they feel an endoscopy is warranted. For GERD and Erosive Esophagitis the typical treatment is 30 mg with Prevacid.
Many doctors will tell you to just take two of the OTC Prevacid if they’ve given a diagnosis. I wouldn’t get in the business of self-prescribing unless you’ve talked it over with a doctor which you should have already seen.