Definitely see a doctor before you talk to the driver's insurance company. They should let you file a supplementary medical claim at a later time, but easier to take care of everything at once. You did get the driver's insurance information, right?

Receipts shouldn't be too important if you can show them the damaged equipment. If you don't file any medical claims, they may be more generous with their equipment damage claim (paying replacement value without depreciation). Don't let that deter you if you have legitimate medical issues, of course.