OCD of being molsted?

Back when I first had OCD I had an extreme fear of any adult in my life having bad intentions toward me. I had another dream of my grandmother admitting to molesting me, and when I woke up,I felt sick.
I try to picture her hurting me in real life and I can't because I have no memory of my grandmother touching me. I used to be scared of using the toilet when I was younger but I don't remember it being due to any sexual abuse, my parents have said it's probably down to aspergers.
My grandmothers a little weird, she some times says things to people that make them uncomfortable. My younger sister sometimes asks her to help her in the toilet but my grandmother always seems like she doesn't really want to.
I don't want to talk to my therapist about this because I don't want to put the idea in anyone's head the my grandmother sexually abused me. I have asked my sister if she has ever touched her and she says "no,".
I feel paranoid about stuff like this when I've usually ran out of things to fuel my OCD.

Hi Shyfemale,
I can't really offer you any advice, but I can day that I can definitely relate to this one, and empathize with you. I'm so sorry that you are invaded with these untrue thoughts that cause you extreme discomfort. For weeks, I couldn't be around my dad because I had intrusive thoughts about being molested and not remembering. The hardest part for me was that in reality, there is very very little chance of it being true, and knowing this, the amount of guilt I had for having the thoughts was crippling, especially since the feelings of disgust and violation were so strong. What helped me at least a bit was to rationalize the thought and label it as OCD.. to try to think more rationally, and more grounded in reality. All the best.