related to accident

I was hit a couple days ago. I was on a slippery hill with my hazards on, the emergency break on, and in park. Someone came up behind me and failed to stop, hitting me and propelling me from the top of a hill to the bottom of the hill into a sidewalk. A couple minutes later, another motorist turned on the same street to go up the hill. 4 or 5 people were waving at her to stop but she gunned it and slide back down right into my car. Surprisingly, the visible damage was not bad so it wasn't towed. Today I decided to try and drive it as I was to get it looked at. The car was nearly impossible to stear. I am wondering what some possible invisible damages may be. How hard might I have been it to be propelled down an entire hill yet visible damage is somewhat minor? What are some complications I should look out for? 
Thank you!