Have a shallow dug well. The well ran completely dry. Before I realized it, used all of the water in system including hot water tank.Finally got water in well -2 months later.Had to prime pump to get water. Couldn't gt the primer plug out so had to take hose off the pressure tank to prime. Now pump will not stop running and it takes least 30 minutes or more for pressure to build up to 40. If I let it run, it will continue to go up----very slowly--to 50-55 but this takes an hour.
I shut it off and I can flush the toilet a couple of times and use a little water before the pressure drops down to 10 or less and can no longer get water. I replaced the switch and the tube from the switch to thepressure gauge . Same thing. Checked the valve on top of tank and air comes out... no water.
This is an old pump.

How many pipes go into the well, one or two? If it's one, then be aware that your pump becomes inefficient at around 20' and won't pump at all at much past 25'.