Guilty,guilty,guilty!

Hi,guys! I'm 18 and I've been struggling with POCD since the age 11. My psychologist says I have a behavior of someone that was molested on childhood but I don't remember being ever molested. Anyway,I have some guilty inside me that i have to out of my chest!
In the age of 14,I once masturbated while i was sleeping in bed with my little sister and my dad (Sorry for talking about something so personal) and I remember doing it as well while my sister and her grandmother were in the room i was,she was little and I don't think she ever saw me doing it because i had a sheet over me. I wouldn't do that again in the age I am now,i know it's wrong,even because she was awaken sometimes but i feel really guilty and I think I deserve nothing but pain. I feel like i've molested my sister I don't know why! I just want to go back in time and fix my mistakes! I feel like I deserve no happiness in life.

You were 14 when this happened, please keep this in mind always. Kids do weird things.
You're fine you deserve happiness.

You absolutely haven't molested your sister. Please keep telling yourself this because it is true.

Maybe what you did was a little stupid, but you were a child - clearly it had nothing to do with the presence of your siblings and absolutely no harm was done. You're not guilty, guilty, guilty - no siree.