I agree with Mr Shamtoub & Ms Allen. You should be covered by your employer's insurance but you need to contact the insurance carrier or have your employer do it because you usually have only 30 days to respond. So....... You need to do this immediately!
You can try calling Community Legal Services at McGeorge School of Law in Sacramento to see if they will take your case. It is a program that represents indigent clients for free if you qualify. Law Students work on the cases with lawyers supervising them. If you do not have any luck with that program most lawyers in the Sacramento area will give you a free consultation.
The person who rearended you is responsible for your damages. If someone negligently repaired that driver's brakes then they would also be on hook. If you are going to be jerked around you need to talk to a lawyer asap. I have offices in Elk Grove and Sacramento and would be glad to meet you for a free consultation.