First, make sure pump turns on at a set psi, usually around 30psi, and turns off at a higher psi, usually around 50psi. Those numbers can be slightly different, but should be consistent.
Then with no water turned on anywhere, observe that the pressure stays at the high reading. If it goes down, you have a leak.
If the pump turns on and off constantly, you might need a new pressure tank.
Normally, running water from multiple locations would not cause a breaker to trip. If the pump is running a lot, the breaker may be getting warm and tripping due to the breaker getting hot.
Also, breakers go bad. You might just need a new breaker.