O/P never logged back on after creating this thread (I checked her profile) so most of what anybody has to say is sort of academic.
That being said there's one point she mentioned I'd like to address that basically echos Zyglamail's points ... whenever I see that someone is on a medication like Zantac and suffers weight loss issues a bell goes off in my head. When I developed gluten intolerance I first had the classic symptoms -- e.g., weight started falling off despite no change in activity or diet, gut pains and chronic diarrhea. After a month or two of this everything changed: Now I was gaining weight and had what seemed like constant heartburn. Took me a long, long, long time to figure out the reflux came on whenever I ate anything that contained gluten -- and since I was a vegetarian at the time I consumed whole grains with most meals (I actually was a healthy eating vegetarian).
My point is that doctors are so damned quick to prescribe proton pump inhibitors instead of recommending the patient try allergy elimination diets. IMHO, if you keep consuming a food that your body cannot tolerate (you don't have to be fully allergic just intolerant) even if you suppress the obvious symptoms you can still create a situation of inflammation and set yourself up for leaky gut and a host of other autoimmune problems which can potentially make weight loss virtually impossible.
Also the OP never mentioned her age but if she's over 30 I'd be curious to see what her full hormone panel looks like.
ditto on an accurate hormone profile