Sorry this happened to you. What you are hearing from others is right, the insurance company will be all sugar to you right now trying to get you to settle cheap.
If you have not done it, get a physical like was suggested. Get x-rays and an MRI. You need to know NOW what damage is there so they cannot jerk you around later, and believe me, unless you settle in the near future they will use everything at their disposal to make you out to be a money hungry, sue happy person. Get a good lawyer ASAP and stop talking to the insurance company directly. If they can cut out the lawyer then they reduce the amount they will have to pay considerably.
After a truck ran over me on my motorcycle in '98 it took months for symptoms and problems from 3 bulging discs and a compression fracture to show up. You might feel good now but protect yourself and if possible put an open ended medical claim clause into your settlement so if you have future problems they will have to pay medical on it even after your settlement. Good luck, I hope they make everything right.