1994 Chevy Cavalier 99,688 bottom radiator hose is coldl

My 1994 chevy cavalier rs the bottom hose is cool when running the upper radiator hose is warm also the radiator cap isnt hot after going a few miles. The temperature gauge is working ok and I got lots of heat from my heater. The temperature gauge goes to 195 then drops to 150 then goes back up to 195 is the fan supposed to be working while driving or just sitting still.I was told alot of things. The thermoatat could be stuck open also I was told if the temperature gauge is moving like that it could be a seaping head gasket I find that hard to believe could anyone give me any answers or ideas on what it sounds like Thanks