Call 911. Always call 911. And make sure to do so within 24 hours of the accident.
As far as what you’re saying to the police, you should be clear, concise and truthfully describe the facts of the incident.
Make sure to mention whether you are suffering pain, and be precise in describing which body parts are hurting. The police and ambulance personnel will jot down your complaints and injuries, which will appear on the police report or EMS report.
If there is a witness make sure that you get their information into the hands of the responding officer so that the witness will appear on the police report. Just try to be accurate, clear, and quick with what you’re telling them.