95' Mazda 626 Overheating

My 95 Mazda 626, been having problems, temperature goes up and down sometimes almost to the top, while driving and idling, heat also blows sometimes hot sometimes cold ait, i was told could be a thermostat or water pump should be replaced does anybody know? I would appreciate.

With the engine cool, make sure the radiator is full and the overflow bottle is about half full.

By doing this would I be able to find out what is the problem??? Cause sometimes it seems antifreeze been also disappearin!!! Thank You

Did hellokit’s suggestion help? If not, an intermittently sticking thermostat could be culpret- when it’s stuck closed, engine heats up, and you get hot air; when open too long you get cooler running engine and not-so-hot air from heater, but maybe first get cooling system pressure checked to see where antifreeze is leaking.