what could be causing my 2001 v.w. jetta to overheat

Head gasket.

you don't think it would be the water pump? How would i be able to tell if it was the head gasket? would you be able to see something in the oil or through the exhaust ?

You might see white smoke coming from the exhaust or milky mix in the oil if the head gasket is bad. Another test is to fill the radiator when the engine is cold and when you start the car, with the cap off, look for bubbling action coming from the radiator or that milky gunk. You could also do a compression test OR a pressure test. But lets hope its just the water pump.

Look around the water pump and see if you can see any signs of of leaking. If you can get your hand on the water pump pully, try wiggling it to see if there's any play in it.

Thanks for your help

I believe there an issue with water pumps from that era having plastic impellers that deteriorated and/or detached from the pump shaft. If you haven't ever replaced the pump...do it.