Struggling with life after a car accident

Several months ago, I was in a car accident. It wasn't a fatal one, but I had some serious injuries and had to have surgery due to having two bust fractures in my lower back and fragments in my spinal cord. Recovery was hard, I lost a lot of weight, which I can't gain back no matter how much I try. I can't get into a car without feeling like I'm going to throw up, I start to get extremely anxious, and I'm constantly paranoid that something will happen. I wake up in the middle of the night covered in cold sweat from nightmares about the crash. I've become emotionally unavailable, I feel totally spent, I can't concentrate in school, and my grades are declining. I've also become very nervous, and I can't stand to be around people. And I get angry over the smallest things. If someone can give me some advice, I would really appreciate it. I just want to stop feeling like this.