During a traumatic event, human physiology and psychology kick in to fight-or-flight mode and each individual gets through the event on an individual "auto-pilot" to just survive. Then, even years later, the mind begins to attempt to process the experiences and PSTD can often develop as a human response.
I experienced several traumas in a row a little over 2 years ago, and I'm actually struggling with PSTD after all of this time. So, the sooner that you find a counseling therapist that specializes in trauma/sexual trauma and get in touch with the Victim's Services resources that are available to you and take action to report the crime, the sooner you'll be able to identify and manage these crippling symptoms.