Symptoms suggest a leak in the pipe from the pump.
The overload switch had operated, which indicates too much current (Amps), which is related to too much water being pumped, or to some drag in the motor/pump system.
If there was so much drag that the speed was pulled down, then it should have tripped the overload quite quickly.
I suspect that you may have a supplemental check valve (the pump probably has one also) somewhere above the pump, either inside or in the line somewhere. That would hold the pressure in the tank.
I also suspect that you may have a break in the pipe below that supplemental check valve. That break is discharging the capacity of the pump at lower pressure so you aren't getting the usual pressure at your tank.
1. Search for another check valve.
2. Measure Amps on the pump while running and compare with specified Amps for the motor. You will need a clamp-on ammeter. Amps greater than the motor rating says the pump is pumping a lot of water but that it is not getting to the tank. Low Amps suggests that the pump has lost a stage or impeller diameter and is not delivering the required head and flow.