Hey OP.

I'm a 22 year old female and I can say I was pretty similar when I was 17 years old. That's when I started getting an interest in gore and these darker images. I was severely self hating and thinking in the way you said was a coping method I used. I still struggle with self loathing and self image, but I talked to my therapist about this very issue a few weeks ago. I was afraid to admit that I thought about such things like brutal rape, beheading, dismemberment, etc. but therapists (thankfully) are non-judgemental. She said as long as you don't ACT ON IT (which I see you said you won't be, good for you!) it's actually a rather healthy coping mechanism.

If it helps you feel better and you don't actually get hurt in the process while feeling like it furthers you towards feeling better about yourself, I say don't be ashamed or feel like there's anything wrong with you. I'm sorry you're struggling with such tough and painful feelings, but (corny I know) I can promise it gets better as time goes on.

Best of luck to you OP. Much love.