Why do I lose water pressure. I have decent water pressure for a few minutes, then after a while I begin to lose pressure till its almost not flowing at all. Is it my pump or bladder tank. Please help, thanks.

Hard to say. Do this: Let your pump run until it pumps up to cut off pressure and shuts off. Write down that pressure. Now run water from an outside faucet into a 5 gallon bucket. See how many gallons you can get before your pump cuts back on. Record that pressure, too. Now, as the pump runs, see how long it takes to get a full 5 gallon bucket. Do that twice. That will tell you how much volume your pump is delivering. Get back to us once you have that done.

BTW, I doubt that your problem is the pressure tank.