Thanks for posting your query at DoctorSpring.com
I am Dr.R.K and I am pleased to assist you.
GERD does not cause weight loss.
With history of weight loss, abdominal pain, gas and tingling, I would like to rule out malabsorption syndrome. There are many different causes for malabsorption.
A complete blood count, stool analysis ( which is already done) and an upper GI endoscopy with small bowel biopsy may be done as initial steps in the evaluation of your symptoms.
You can discuss with your doctor about these tests.
Get back to me with these tests results.
I hope that answers your query.
Let me know if I can assist you further.