Another possibility is that there is a leak in a pipe that is losing enough water cause the pump to operate at a the far right of the curve where the head is low.
With such a shallow well I would pull the pump and check the flow and pressure. You could start by disconnecting the pipe to the house and check the pressure at the top of the well. If that is high then you may have an underground leak. If that is low, pull the pump and run the test.
DO NOT shut the valve completely.
A properly sized 3/4 HP pump for that depth should produce somewhere in the range of 10 to 13 GPM at 60 psi. It should easily produce 100+ psi.