What Causes Tiredness, Abdominal Pain And Nausea With History Of Rectal Cancer?

Hi .I am 57 years old female I have been feeling very tired for last three weeks.Recently I have experienced dull abdominal pain in the right upper quadrant of my tommy accompanied by nausea. I have not noficed skin or stool discoloration .6 years ago I have undergone surgery for stage I rectal cancer, treated with A P resection and colostomy, without radiation therapy of chemotherapy.Last June I was discharged from hospital care. I am married with two grown-up children. Can you tell me what may cause my symptoms?