1997 Lumina RPM's running really high in park

I have a 1997 Chevy Lumina. Recently my car is doing interesting things. When I am reversing slow, and trying to drive slow, my car wants to race to go, and it has never wanted to do that before. The RPM's shows 2 when it is resting in drive. Then, when I put it in park, the RPM's go up to 3 or higher, like I have my foot on the gas and I am revving the car in park. I end up turning my car off really quickly, but I do not know if this is something I should worry about, or fix right away. Could you please help me?