Sounds like you blew the gate oxide handling the device - most MOSFETs are extremely static sensitive as they have no protection devices built in. Touching a MOSFET just by the gate pin when the other pins are
grounded is likely burn it out - the human body picks up dozens of volts of mains pickup which exceeds the
gate-source voltage spec. Keep MOSFETs in their anti-static packaging until they are safely in the circuit.