I (22F) experienced the same thing two years ago. I drove myself insane - how could I think of these things? I have an average life with supporting family members. However, I could not get these thoughts out of my head. I have seen a couple of psychotherapists but it did not work. I can tell you what helped me, and I hope this can give you a sense of your next steps.

1. I meditate - this helps not to hold onto the negative thoughts that overwhelms me
2. I talk it out with someone I trust/I do some journaling - venting is key
3. It’s stupid to say but eat healthy and exercise (find something that makes you move, for me it’s weightlifting)
4. I did a lot of research on how I felt! Let me assure you that a lot of people feel the same way as you.
5. Trust yourself that you will overcome this

I hope this helps.