(((Steiner of Thule)))
I know all too well about those negative, intrusive thoughts. They tell me and sometimes yell and scream at me about everything bad about me. How I have no right to breathe air, and other awful things. I've had these thoughts my whole life. I thought it was "normal", but somehow knew it wasn't, so I never shared with anyone I thought that way. It's wasn't until my mid-40's that I got medication. The thoughts got less frequent, but still showed up from time to time. When they get worse, my meds get increased. The thoughts go away or become whispers that I can turn off.
Between the meds and therapy, I've made great strides, but thoughts are not governed by a toggle switch. I've got 40+ years of thoughts to get rid of, and it's a long exhausting process.
Hopefully, at your young age, your process won't be as long nor as exhausting.

I LOVE what Hooligan wrote...26 reasons why you try. I think we should make a poster of that!