What causes loss of appetite and being lethargic?

Consider this...: Gi tract has a limited # of symptoms to signal its distress--nausea/vomiting, diarrhea/constipation, bloating, pain, fullness, bleeding, etc. Many of these characterize ibs, but are also seen with inflammatory, infectious, ischemic, malabsorptive, metabolic, ; functional disorders. Directed lab work, imaging, biopsies, stool studies will find your answer ; direct treatment. Chance of pregnancy?