I have the exact same problem as yours. The order is different though. I first had chronic diarrhea which was eventually diagnosed as microscopic collitis, then I started having GERD and nausea. My dr seems to imply the gerd episodes are stress related...
I am interested in looking at alternative/natural remedies to address the problem. I eat very carefully (no alcohol, smoking, or lactose, fried, spicy food - eat lots of vegetables, fruits) but that is having no affect whatsoever. The dr also thinks that is not the solution for me (he says eat whatever you want but keep it simple, never says don't eat x, y or z). Also do yoga regularly.
So theoretically I am doing all the right things but am still not going through a particularly bad episode. At this point I am pretty desperate to try anything.