Hi ! As you have got a Ventriculo-peritoneal shunt , your abdomen is prone to infection due to this. Any infection in the abdomen (peritonitis
) will reduce the appetite, will make you feel nauseous and will hurt your abdomen if touched or if irritated.
Another possibility is blockage of the shunt causing increased intra cerebral pressure causing nausea
with feeling of tiredness
If the symptoms persist or increase , then I would suggest you to see your treating doctor without any delay for further check up and needful.
Wishing you an early recovery.