Ir means you are sucking air due to a suction leak in the plumbing or the water level in the well is at the foot valve inlet screen. You could have a split in a pipe or fitting or a leaking/loose fitting.
You can adjust the switch cut-out setting a lb or two but any leak will probably get worse with time. A water leak can lead to a lose of prime. If the pump doesn't have a safety cut off switch, you could burn up a motor if it doesn't have a thermal overload protection.
Quality Water Associates