what is causing my 08 sentra to shrill so loudly when I accelerate because my rpm gauge reads 5 and my speedometer suddenly went from 16 all while still driving?

I was coming back from a weekend trip that was about 200 miles away from home and
suddenly my 2008 sentra began shrilling like a siren...more so if I accelerated. And the
louder the sound the higher the rpm gauge read and the speedometer began flashing
and went up to 160 and down to zero all while still in motion. And finally the check
engine light came on. I have 86000 miles on my car and one week ago i got a tune up
and had my breaks worked on. My car was feeling like it did when I first bought it.  
Needless to say I was devastated. There's no jerking or anything going on and the
engine is so quiet when it starts I can barely hear it. So what could be the problem?
Any assistance would be greatly appreciated.