My gas gauge stopped working,says it's full,I go to put gas in it and can't get gas into tank ,it wants to come out,but knowing it's empty,was wandering if it needs a new sensor?

Putting gas has nothing to do with you fuel gauge problem
Must problems to add fuel and comes out can be cause by air flow in the tank, also it is recommended to fuel with the engine turn off so the pressure from fuel pump going back to the tank will not affect the fueling , about you fuel gauge not working properly can be cause by a electrical problem such wiring or defective gauge or can be fuel sender problem with most the time it is install on fuel pump assy.