the main ways to tell if your head gasket has gone are water in the oil (the dip stick and oil filler cap will be white and creamy) or oil in the water (water will have an oily film) of course with either of these you will not actually loose fluids. if you are loosing fluids then check for steam or smoke coming from the exhaust.
if you are experiencing none of these, then its time to check the cooling system, first check to see if the cooling fan cuts in when hot, if it doesn't then its the temperature sensor, usually screwed into the radiator about half way down. if it is working then change the thermostsat!!
good luck with it!
Mike Payter, May 2006