Can anxiety and worry cause skunk smelling poo, diarrhoea, chronic stomach pain, rib cage pain?

Check with your MD: Yes, anxiety can cause a variety of physical symptoms, including vague aches and pains, and occasional diarrhea. But symptoms you describe could also be signs of a serious physical illness. You could have GI illness like spastic colon or Crohn's disease, or pancreatitis, or a tumor. Please see your physician soon for a physical workup and lab tests. If everything checks out OK, treat anxiety.