i had a what i think was an intrusive thought. i really hope it was and that it wasnt me

i think my intrusive thoughts are real. what do i do now man

Basically I had a bad violent intruisve thought and I was scrolling through instagram story and on the chat box underneath my mind made me write it down on the reply box but I didn’t send it I wrote it down then got rid of it liked cleared it now I’m like why did my mind make me write that . ! Now I’m like omg why did I write that will anything happen or am I overthinking?

I wanted to ask if it is possible to purposely think of an intrusive thought and then shifting your mind instantly to something else? Is it still an intrusive thought if you have been thinking of it 'purposely' for a second? I dont know how else to explain it, but it felt like I was purposely thinking of it. Anyone else had similar experience what happened during intimate moments like masturbation I feel so ashamed cuz the thoughts are so bad they're either about family members children and stuff like that it feels like I think it I just want to know if I'm not alone I feel like a monster because it feels like I thought these things or like I did think these things and I don't know what to do I feel so ashamed and grossed I need help I just want to know if anyone had a similar experience to shed light on because I don't know I feel so isolated