Car won't go in reverse and drives when it is in neutral. Whats wrong?

I place the car in reverse, and it moves forward a little then moves back a little then just stay there even after i rev. I put the car in neutral and it acts as if it is drive. I can press on the gas and it moves forward. If i shift into neutral while i am already moving from being in drive going around 30 mph it acts like normal neutral. The car shifts gears fine and moves forward fine. 1996 corrola