Go to a physician.
Don't rely too much on things that contain calcium carbonate because you can give yourself a kidney stone.
Consult a physician, rather than asking for advice here. I'm sure the replies are all well meaning, but what helped for someone else might not help you.
Best to seek professional medical advice that can be tailored (I hope) to your situation.
Avoid acidic foods. Eat cucumbers, greens, etc which have a cooling effect on your stomach.
Raise the head of your bed an inch or two. Sleep on your back. Gravity will help keep the acid where it belongs.