Pressure drops when pump kicks on
I have an older well with a two year old pressure tank. It worked fine all summer, even watering my lawn. Lately the pressure in the house seems to drop after a few minutes of use and cannot build back up unless you turn off the faucet or shower. My switch shuts off at 56 and kicks on at 40. When it kicks on it immediately drops to 10 and will not get any higher until I shut everything off in house. The pressure in the tank after draining is 38psi.
Any ideas.
Thanks