Burning stomach is pretty normal after quitting PPI's. It should go away when your stomach acid production gets back to normal, but it might take a couple months.
Meanwhile, eat a bland diet, small frequent meals, and try using antaciRAB such as Tums or RolaiRAB to relieve it. If those don't work, try an H2 blocker such as Zantac. H2 blockers do some of the same things as PPI's, but they aren't as strong, so they make a good "step down" drug for people trying to quit PPI's.
If it doesn't seem to be subsiding, or if the pain becomes really severe, obviously get it checked out.