You said the pump in the well, so I have to assume it's a submersible. They do not need to be primed. But they do have to be in the water. It sounds like your pump and water level are very close to one another. You may need to lower the pump deeper into the well.
You may be in a draught, this causes water tables to go down, or maybe the well is just not producing as much water as it once did. Either way, you may want to either put an amp meter on the wires and see if they drop when the water stops flowing. This would indicate the water level dropping below the inlet of the pump.
If this gets to where the water stays off for a long enough time, it could nuke your pump.