No water pressure!!!

I bought a cabin in July and the water system ran good. They system has an above ground pump. I had the water lines inside all replaced. I then noticed that the water pressure would drop after about 5 minutes in the shower. The problem has gotten worse. I replaced the pressure switch and the bladder tank with no luck. The pump constanly runs and I have no water pressure. I did notice that when I shut the valve between the bladder tank and the house, the pump shuts off like normal. With the valve open, I can hear noise in the pipe between the house and the bladder tank. Is this an indication that the line between the house and the bladder tank has a leak? Any help is greatly appreciated.

You have a leak somewhere after that shutoff valve.