Can I sue the insurance company?

I was hit by a progressive driver who fell asleep at the wheel and came at me head on. She did receiv a citation for the accident. This accident has caused me nothing but pain and heartache. I have been seeing my doctor and chiropractor for the damages to my body, which were throacic/muscle spasms and sprains, this diagnosis from the emergency room. My emergency room bills totaled to a little over 3000 and my chiropractor bills were $3600 and my primary care doctors bills were 402.00 I also had prescription costs of about $86 which were co-pays. My car was completely totalled and I have about $8000 in doctors bills, and now the insurance company is trying to settle with me for $5000 saying that all the bills were not reasonable. I am still under the care of the doctor because the pain has not subsided and I do not know when it will. I was expecting to be over this by now as it has been since December 11. But I am still on medication from the doctor because of this. I do not have an attorney, I am still on medication for stress, pain, and insomnia, my blood pressure has been elevated since the accident, and I have never in my life had this problem. Up until this accident I have always been in perfect health. This insurance company is telling me that they will not go any higher on my settlement. I do not have an attorney. Can I sue the insurance company for my medical bills and pain and suffering? They have already accepted liability and settled the claim for property damages.