Whiplash injury and going to court for settlement...?

[CTU]

I was in a car accident last year and suffered whiplash injury. My lawyer is going for pain and suffering. The accident wasn't my fault. The driver responsible for the accident, his insurance made me see one of their doctors a couple of weeks ago. He was really rude. Now, they want me to do a psychiatric evaluation on this coming monday which will last 4 hours. He will probably be rude also. This is really stressing me out! What are they planning to do to me for 4 hours? Is he trying to prove that I'm crazy and the pain is in my head or what? And, if he is too rude, I will probably tell him where to go and just leave which isn't going to look good for me. My lawyer told me I had to go through with this if we want to pursue this. What happens if I refuse and can I trust my lawyer? Couldn't he have said that it's too stressing for his client? I do not know what to do anymore. Has anybody gone through this before and if so, what did you do?
Sometimes, I feel like just dropping everything! Is the settlement really worth the stress? I haven't slept all week, I am really nervous going through with this!