1996 Pontiac Sunfire car has water light on.

I recently noticed a water light come on. I have a Pontiac sunfire 96. I have replaced the water pump and the thermostat. As well as check all hoses..... on the dash board where it shows how hot and cold your car is I noticed when it is running it will not go in the middle it says on 0. This was five days ago, today I get into my car turn it over like normal and the water light is off but everything is still doing the same thing by saying in the middle on zero. So I would really light to answer of what my problem might be and how I can fix it. I do not think it is a radiator problem, but please let me know if it might be.