After having gone through a bad accident personally (had my left femur fractured), and getting a bad lawyer, and getting completely hosed from the experience, later in life I've helped quite a few friends deal with accidents and injuries that have worked out way better than mine.
First thing you need to do is take any and all doctor visits, and save the receipts for everything involved. X-rays, prescriptions, amount of advil you use to reduce headaches and body pains, just simply everything.
When you do talk to the insurance companies involved, just simply state "I was driving in my lane, and the truck ran over my car." Don't ever say that you tried to avoid the collision by swerving. Don't say that you braked hard to avoid the accident. Just say you were driving along, and were suddenly hit by the truck. You were fully in your right to be driving in your lane, and the other vehicle violated your vehicles physical body structure, putting them at fault (if this is the case, that is).
When it comes to the replacement value of your car, use Craigslist and cars.com, and dealer prices for any vehicle that is 100% like yours was, even if its halfway across the US. If they lowball you (and they typically will initially), just say that's no enough to replace your vehicle, and send them the links to the ones that are identical matches. They will revise their amount, and make sure to add on the cost of registration, plates, and transport, if it is halfway across the US. And stick to your guns on this one. Tell them you won't settle for less, even if it takes them 5 months to give you your money. They will fold when they hear those words, most insurance claims adjusters get bonus' for closing settlements quickly.
As for your personal injuries, and compensation for that, take your medical bills, and that's the number to start with. They have to comp you 100% for that. Pain and suffering, I say multiply the bills by 5, add in the cost of replacing the car, and ask for that. You get to negotiate down from that, but having a truck tire coming straight at your face is really, really traumatic. Let them know you have trouble sleeping at night, because this image pops up a couple times a week.
Its been almost 13 years since my accident, but I still have moments of unpleasantness when I think of slamming my motorcycle into the side of the Grey Acura Integra 4 door that blew the stop sign in front of me. If really, really sucks at times. Sometimes when I approach an intersection, and the vehicle doesn't seem like its going to stop, I have an instant of panic, which I have to let go of. It still affects me, day to day.
You will have this too, I guarantee.
Let them know it.
Don't accept that you have to go uncompensated for this mental image floating around your head for the rest of your life. If you can, go to a couple of sessions with a physiologist, and talk about this mental image, and have those included in your bills. It will only support your claim.
But, overall, you don't "need" to get a lawyer involved, unless the insurance companies are trying to bend you over, and make you accept their policies someplace you don't feel comfortable having them placed.
I've helped a bunch of friends over the past 13 years this exact way, and they always do a heck of a lot better than I did with the help of a lawyer. Maybe they might have been able to do better with a lawyer? Who knows...
But in the end, you have to be the one happy with the settlement, not your lawyer, and not the insurance companies.
BC.