Here's a MedLinePluslink to drug info on Zantac and similar drugs:
You can also access the MedLinePlus diseases database from this link. Aside from Gastric Ulcers, suggest you also look up:
IBD [Inflammatory Bowel Disease]
IBS [Inflammatory Bowel Syndrome]
GERD [Gastro-Esophogeal Reflux Syndrome]
The above diseases have some of the same symptoms as gastric ulcers. Reading up on these may help you determine what you should watch out for, what you should do and what you should avoid.
Question: Why didn't your doctor prescribe antibiotics? Gastric [or peptic] ulcers have been shown to be caused by the H. Pylori bacterium. I believe that the current research has shown that only antibiotics can kill this bacteria.