Hi, I read some of these other questions first and have summarized my question with that information. I have a two story home, less than 3 yrs. Old, pex tubing, well, pump, and pressure tank. In the last few months the water pressure has seemed to really diminish in the house. If I turn on the shower and flush the toilet, the pressure is gone until the toilet refills, or if you flush the toilet there is no sink pressure... I am wondering is there a posssibility that the pressure tank bladder has lost it's pressure, and can I repressurize it. While showering, the water pressure fluctuates up and down rather rapidly. (25-30 second cycles) The entire house is really suffering including the hose spigots outside... I am not sure where to start? Thanks for your help. Jimmy

Sounds like your tank might be waterlogged, which is to say there is no air in the tank. This will cause the pump to short cycle, producing what you are experiencing in your shower. Rapid pressure drops and rises. You can usually track this by watching your pressure gauge with a faucet on. You will be able to see this easily. Your tank should be able to give you five or six gallons (at least) of water before the pump cuts back in.
Your bladder tank has an air valve at the top. Press that and see if water comes out. If it does, then the bladder is ruptured. You can also use a hammer and lightly tap the tank, beginning at the bottom and moving to the top. You can generally tell from the "tone" of the taps when water stops and air begins. If the tank is full of water, then the bladder is toast. Short term, you can refill the tank with air with the air valve on top. Turn off power to the pump, drain the tank by turning on a faucet. Add some air as the water falls if you need to. Once the tank is largely empty, you can turn on power and use the tank. Long term, however, you will want a new tank. The air in the tank will gradually dissolve into the water until, once again, there is no air in the tank.
I might add that losing a tank in only three years is kind of strange.