Talk to your therapist about it or show them this publication. It's already at the cutting edge if you have a therapist. Just say that I think I have post-traumatic stress disorder and start talking about your symptoms. If your therapist dismisses you or doesn't talk seriously to you about the evaluation, you may need to find another therapist.
It definitely seems like you should ask to see a doctor because of the trauma of being in two car accidents. You're very brave and I know you'll feel better when you talk about it (I know I do), and I think you'll feel much better if you talk to your doctor about how they can help you. I've found that as long as a medication has terrible side effects and no one wants to take it, it's easily available and doctors will be happy to give it to you. I was afraid to tell my doctor what had happened, in large part because, like you, I thought it wouldn't be worth asking.