Sudden death of a loved one can be very traumatic and it seems in your case that the death of your brother has left you totally incapacitated. In mourning over the death of a dear one it is important that one accepts the reality of the loss, acknowledge the pain of grief and move on with life by adjusting to an environment in which the deceased is missing. If any of these psychological tasks is not achieved spontaneously within a reasonable time, problem of grieving may ensue.
Give yourself time to grieve over the loss and take the help of close family and friends in dealing with the grief. You may also seek professional help of a psychotherapist to deal with the loss.