Good Morning,
I think you have every right to feel afraid and need to know what happened to your son.
I am not a professional but I do not know that finding out what happened to you will help our son right now. If you have repressed your assaults it could take a lot of work with a therapist trained in this field to get you to remember.
However you son needs you to advocate for him now. I agree, sit down in a quiet place and talk with him. Remember if he has been molested he may have been threatened if he tells Mommy something bad will happen so you have to get him to understand you are safe and no one will hurt you.
If that does not work I would take him to your pediatrician and ask for help but do not let him spend any alone time where this trauma may have happened. Until proven wrong I would protect my child.
Bless you and I will say a prayer for you.
Kitt