What to do if sudden loss of well water and pump is still running?

what to do if sudden loss of well water and pump is still running?

Sounds like you've lost prime. Turn off the pump and open up the small hole on top of the impeller housing, (there may be a gage or a plug installed).
Fill the impeller housing with water until it overflows. ( If you can't overflow it let me know) Replace the plug or gage and turn the pump back on. This should get your pressure back. Good luck and thank you for rating my answer. Tom