Please share this with any close family member or your family physician or any psychologist.  This person should be matured enough to help you handle the emotions and also help you deal with the past. Since you were very small at that age, the thoughts about the  incident has got deep in your subconscious mind. If you consult a good psychologist, she will help you to deal with this  trauma of past. Of course you can'tgo in the past but you past and change the situation there, but The good thing that a good psychologist can help you put the right thoughts in your mind so that you can find your steps to deal with it.