I saw three people die this morning... i can't go on living =/?

It is not a question of why should you live and not the little girl. It is a question of how will you deal with the trauma you are going through right now. What will help you deal with what you have witnessed? Have you spoken with your parents? I know talking with a grief counselor will help tremendously. Realize right now that there is NOTHING you could have done to change what happened. Take the lesson of today and make it into something that can help others. Talk with your school principal and ask to speak at one of the days that the school gathers for things and ask if you can talk about what you saw, how it affected you and the dangers of texting while driving, the dangers of speeding etc. Perhaps send flowers to all the families affected by this tragedy. I am so sorry you had to see this.