As Joy recommended, and if one PPI doesn't work for you, ask for another. I only got relief from Nexium, but my sis is OK with Prilosec. Some work longer than others - google "duration of action." I found Zantac helped too, took that one in the evening.
Timing of the meds makes a big difference too! I found taking PPIs a half hour to an hour before breakfast, and making sure to eat at least a little breakfast is important. The pills depend on you eating breakfast! They will not work nearly as well without it.