inconsistant stool, lupus meds, and other fascinating personal issues.

Over the last two months or so i've been having some abdominal pains/cramping/bloating, and seem to be swinging between constipation and diahrrea (sp?) -- sometimes with truly noxious smelling fumes. It doesn't seem to matter what I eat, since my diet stays mostly consistent and I can't see any connection between particular foods and the symptoms.  In the last couple weeks I've been getting... heartburn? I don't know. I feel like I'm going to be sick right after eating, and it will go on for hours. It doesn't *burn* - just feels like I'm going to throw up. I also have really bad gas now -- for the past year, when prior to that I hardly had any, relatively speaking.
I am currently taking Hydroxychloroquine for lupus, though I only started it about two months ago as a test -- my blood tests for lupus were only borderline. However, none of the above were listed as side-effects, could this drug be causing it, or lupus itself? or. . ?