We have a well system that is 6 years old. Our water pressure has always been good. Lately though, whenever my tub is running at the same time as my washer or dishwasher the pressure subsides substantially until the washer is through filling and/or dishwasher is through with it's cycle. The same is true with all of our faucets. They lose pressure and water flow when another water source is flowing. What is suddenly different?