Is it normal for my air bags not to deploy in that type of scenario and if not, should I pursue suing the car company as well?

I was on the freeway stopped in traffic when the three cars behind me didn't stop and rammed into the back of my car going over 65 + pushing mine into the car in front of me. My car was totaled and my head slammed into the driver side window from the impact leaving me with a concussion/major neurocognitive disorder/post concussive syndrome and PTSD. It has been almost two years and I am still under medical care. My air bags never deployed during the accident which is odd because my car looked like an according after. My seat belt was on.