Maybe try calling a nurse? Sometimes they are available for free thru your health insurance. I would not fool around with chills at this point after a digestive tract operation, it is too easy to get a leak and develop sepsis. If you can, i would just get to the ER. You may need IV antibiotics ASAP.

Of course, i am not a dr, but my old i mean former! landlady had this complication after her colonoscopy. You should not be feeling sicker.