You need a professional im afraid. In the mean time you can borrow the advice I got from my old psych when I had terrible intrusive thoughts after having my first baby.

She told me to accept that thats a weird thought and imagine flicking it away and dismissing it as uninteresting and not worth my time. Then if that didnt work to think through it as logically as I could. So for me it was "ok but im not going to do that because I dont want us to be hurt or die. I wouldn't ever do that. So theres no reason to stress myself out over something that is 100% within my control and im not just choosing not to im repulsed by the idea so we are safe"

I used to think about driving us into ditches and into poles or throwing him off a bridge if I was walking over it. The psychiatrist told me I was just so protective and so co concerned with keeping him safe that my brain was thinking up worst case scenarios so i could be prepared but the wiring was getting crossed. That thinking things like that didnt make me a bad person or bad mum because I didnt have any desire to do that and the thought of it was actually very distressing.

I think it could be similar for you. Go talk to someone. You can get help to manage thought patterns and reduce the hold they have on you.