gas needle constantly stays on empty even when I fill the tank on 2002 Cadillac DeVille DTS

I dont have a code but everytime I go to get gas the car is full it freaks me out becasue the needle stays on empty even after I full up at the pump

Asked by for the 2002 Cadillac DeVille DTS
problem could be the gauge itself, but I would put my money on the sending unit in the tank is stuck or bad. You would have to remove it from the tank to test it. Then replace or repair.