Posted 4/12/2016 12:16 AM (GMT 0)
Welcome to the forum.
You really need to see a gastroenterologist and get some simple tests done. Since you're having continuing symptoms you need to be checked for infection, parasites and what else only your doctor knows.
Changing diet when you never had a problem with it before, I would guess, isn't the answer. There is no absolute GERD diet, only foods that you happen to tolerate. Keep a food journal.
20 mg Nexium is half the prescription dose. Did a doctor tell you to take that? Twice a day probably won't work either because it's a time release pill and should last all day. You also have to take it right. Half an hour to an hour before breakfast, and the you must eat. It takes about 45 minutes for the medicine to get through the bloodstream to the acid pump cells. The pumps have to be turned on by eating so the medicine can turn them off.
I hope you will see a gastroenterologist!