Good Morning, Sorry to hear you are suffering so much. Zantac is an RX drug but OTC is not the RX dose. I would refrain from using the Zantac but that is just my gut reaction.
have you tried liquid Maalox or Mylanta instead of the chewable tabs? Sometimes they will help with the discomfort better then the tabs.
Again I am so sorry your having these issues.
Blessings,
Kitt