occasional intrusive thoughts are normal, it’s only ”sick” or abnormal when they start interfering with your day to day life. as someone else said, the content of them are insignificant. it’s common for intrusive thoughts to be about what we fear the most or find most disturbing and it’s normal to have the thoughts you’re describing once in a while. once a week is fine, don’t worry about it (+ worrying about them generally just worsens them)

if you were to actually have these thoughts 24/7 then it would likely be an OCD issue. it still wouldn’t make you a psycho, it would just mean your brain is vulnerable to obsessive fixations and anxiety.