I have an above ground well water pump and it was replaced about 5 months ago. I have 40lbs of pressure at the pump and the tank has 40lbs of pressure as well. When one facet is turned on the pressure is decent but as soon as another facet is turned on I lose most of the pressure out of both facets but the pump gauge will show around 50lbs of pressure. Any help would be much appreciated.

Did this problem begin 5 months ago with the pump replacement or has it been long-term?

Also, you state you have 40# of pressure, then you say you have 50#. So, we need to know at what pressure does the pump cuton and then at what pressure does the pump turn off. For instance, many pumps will turn on at 30# and pump until the pressure reaches 50#, at which point it turns off. This is referred to as a cycle.