can i sue what should i do

I was sitting at a red light in front of a box truck a truck coming downs the road lost control hit the box truck then after the box truck he hit me he said he was going 55 its a 35 just so you know I was not in immediate pain adrenaline im guessing I went to the hospital about two hours after the crash for shoulder and back pain. they said it was probley whip lash over the pain is still there but im also having neck pain which started that night it is hurting right now looking down to type this I have no insurance medical and cant afford my meds the proscribed me I don't know what to do I feel like he should pay for me to seek treatment and I am scared to death to drive now when I have im always paranoid someone is about to hit me what should I do