Why does my temp gauge go to C while driving??

You may want to check your thermostat it may be stuck open and the coolant temperature sensor isn't able to sense temperature raise because the coolant isn't getting hot in your radiator.

I would think about finding the water temperature sending unit on top of the engine and check the wiring from the top of it and follow it as far back to the car as you can to see if it's against something that would get hot when the engine warms up Otherwise, consider maybe the temperature sending unit may be going out.