Thank you for writing. I’m sure this is disturbing. But it would be irresponsible of me to answer your question on the basis of a short letter.
The human mind is a remarkable thing. When we can’t consciously deal with something, the unconscious sometimes gets activated and helps us through. As you noted, it could be that you were sexually assaulted when you were young and that you coped by dissociating from the experience. However, it is also possible that there is something about sex that is disturbing to you and your mind is helping you by creating a reasonable explanation for your feelings. What you call “playing tricks” may be a way your mind is helping you cope with something in the present, not the past.
The only way I know to tease out what is real is for you to see a qualified therapist who is experienced in working with trauma survivors. Please do yourself the great service of making an appointment. It is too painful for you to live with the unanswered question.
I wish you well.