Well, pressure tank, pump, gauge or all 4?

[jimmylee]

Hi. Earlier today, I looked outside and saw a river flowing outside where my sump pump empties out. I went downstairs to find the well pump and the sump pump running constantly. I turned the well pump off to see if the sump would catch up and shut off. i returned a couple of hours later to find that it had, but when i turned the well pump back on, it failed to fill the pressure tank. I have run it a bit and i find that i can get water flowing in the house, but with very little pressure. the gauge on the pressure tank says that it's full, but when i tap it, it sounds hollow. please help.