Low oil pressure clicking behind radio

High temperature low oil. Clicking noise near middle engine by radio. White smoke or burning oil passenger side under engine towards rear of the car. Passenger side rear under engine white smoke. Turn on car hear ticking pick a clock behind radio. Idle rpm at 1,000. Drive or idle while will say high temp low oil. Gauges don't run very hot. Oil gauge will be little above middle of high then plummets down to 0 all way bottom gauge at L. Then seconds later or sometimes longer then goes back to middle. I think click or tick noise means oil pump. But wanted verify and cross diagnosis so don't get pump if just sending unit act. Just fixed head gasket. Vehicle will shut off and can start back up. Going try find oil sending unit try check for leak and connect but tick makes me think should start with oil pump. 02 sensors are working seems good. Hit me back when see this or get chance. Thanks.