Sorry to hear about your Lyme disease. Has that been treated, and do you feel like you have alot of problems from that? Are you on any other meds? Antibiotics? Antibioticis immediately give me reflux.
What kinds of foods do you eat?
To answer your question, I don't believe that weight loss is a part of GERD, unless the symptoms bother you so much that you don't eat. If nothing has changed at all in your eating, then I would tell your doctor about it.
Are you getting more exercise? Had you gained weight with the antidepressant, and now you're just taking that off? Sorry for all the questions!