1999 Pontiac Firebird Car Over Heating?

Ok. Ill start wth what happened. I was driving one day and about 15 minutes from when I started driving it, suddenly my water temp gauge reached its maximum and my car wouldnt rev higher then like 2200 rpm which caused it not to go over like 20 kms an hour. My engine lights came on. Now trying to figure the problem out in my drive way I let the car sit to cool the engine off and then started it up. It ran fine with the engine light on for about 10 minutes and then the temp gauge hit maximum and I could here a fan running loudly under the hood. Eventually the idle got really rough and I turned the car off not to damage it. I disconnected my battery and the engine light went away. Until I ran it again for about 15 mins and it all happened again. My guess was an temperature sensor? But im no mechanic. Any help you guys could give me would be appreciated it. Thanks