Multiple Rear-End Collision

My question involves a traffic accident in the State of: VA

I was involved in an accident where the driver in front of me was cut off by someone changing lanes, so he braked suddenly. I believe that I rear-ended him, and then the person behind me rear-ended me, knocking me back into him. At the time of the accident, I honestly had no recollection of the original collision - the statement I provided to the police was that the person behind me hit me first, sending me into the car in front of me. The second collision was much worse than when I hit the first car, so that combined with the shock probably caused me to just push the first incident out of my mind. The police ultimately gave the last car a ticket, and I believe the police report shows that the the car behind me was at fault.

Now that I have had some time to think about it, I have realized that I most probably did hit the person in front of me first, and I feel terrible about the confusion. I have no idea what I should do. Should I call my insurance company and admit fault, or should I wait and see what the other people's statements are? If I admit fault, am I liable for both the front car's damage and the rear car?