Obsessive thoughts

I have recently started seeing an ASD counsellor with regards to recent diagnosis (she is going through what my diagnosis means to me ) also she's helping me with regards to the traumatic sexual abuse i suffered as a child.... she seems really nice and is knowledgeable with regards to ASD and abuse counselling and i like her and think i can trust her ... my question is this...

i have horrible constant thoughts for as long as i can remember that involve harm to my son and others i care about ( but mostly my son and a constant recurring image of him on a mortuary slab ) which i cannot eradicate and extremely graphic thoughts of a sexual nature which are distressing considering i find sexual contact rather gross ... my apologies if i have offended anyone but i want to know am i a freak is this something that other NDs suffer from and should i mention it to my counsellor ( im afraid that she will be disgusted and refuse to treat me)