Welcome to our humble home.
Like Out there said seek specialized trauma treatment. Given the closeness of the event I would hope that your place of work would provide a point of contact for help to those that continue to deal with the tragedy of what happened. Maybe this point of contact may be a valuable resource when it comes to seek information for on going issues that you will face.
This world seems to harder and harder to live in. Try and make time where you can to carve out some peace where you can.

Talk to people.......... Cry. Do something to cheer one other person up. This will feed your own soul too.