truck is overheating

i let the truck cool down. added more antifreeze, topping it off. started it up, let it idle in the drive way...checked for leaks. none. everything is tight and where it needs to be. i drove the truck WITHOUT HAVING THE HEAT ON and the truck temp guage stayed between the "r" and "m" of the word normal on the guage. i drove it around the block, did some stop and goes, idled talking to some friends all for about 10 minutes and it remained between the r and m....also there was no smell this time. .so my question is since i didnt turn the heat/ac on is that the source of the overheating?

Is it still overheating?- maybe it fixed itself-

As long at the temp gauge is somewhere in the "normal range" you're OK. From a anti-freeze change (cold) to normal operating temp normally takes more then three minutes. The engine has to heat up sufficiently for the thermostat to open. When it opens it pulls coolant into an otherwise empty block. Naturally, this will cause the level to decrease in the radiator. Once more coolant is added the engine should operate correctly. If the smell went away, there is a possibility you spilled anti-freeze on the engine, especially if you changed the water pump and thermostat. What you were smelling was possibly the coolant being burnt off the block.