Hi there -
The new symptoms (nausea and diarrhea) are not directly related to GERD. It's most likely due to the holiday diet, in which case it should start to resolve after this weekend, unless it's actually due to your having picked up a stomach bug in recent days. That's another possibility, and it also should run its course and get better on its own in a few days.
As for the nocturnal GERD problems in general, one thing one no longer hears much but which is still useful advice in some cases, is to elevate the head of the bed if practical, using wooden blocks, bricks, books, whatever is handy, so that your whole body is resting on a downward slope. This prevents the backup of stomach contents into the esophagus (and often right into the nasopharynx). This used to be a common suggestion offered prior to the development of powerful medications to prevent excess production of stomach acid and also help tighten the lower esophogeal sphincter (LES). However, if the LES is profoundly incompetent, the patient, when lying flat (as in bed, trying to sleep) is going to have some regurgitation of stomach contents regardless, and this is where the jacked-up bed head can be very helpful. It should be raised at least six inches to make the slope effective.
If this doesn't help the problem, and/or if the nausea and diarrhea don't resolve in a few more days, you'll need to be evaluated in person by a healthcare provider.
I hope this is helpful to you. Good luck and I hope you are able to enjoy the rest of the holiday weekend. Follow up with us as needed.
John Kenyon, EMT, CCT
Non-invasive cardiology tech, Emergency and Critical Care technician, Critical Incident Stress Mgmt. specialist