Myers Hydropneumatic Pump Tank not kicking on

I was wondering what could be the problem with my Myers Hydropneumatic Pump Tank it's about 5 years old and when I tun on the water from the faucet the pump is not kicking on and my water is very cloudy .The PSI is about 40 on the gage .My well is about 600 feet deep what could cause this problem this just happen last night .I checked all the breakers and there fine please help .You can email me at mikebynon@gmail.com

My model number for The Myers Tank is MPD20 AND THE SERIAL NUMBER IS JO4212701

Is this a submersible pump or a shallow well jet?