Please help

18+ I had an intrusive thought and kept thinking about it but then I realised I wanted to think about it and I thought it and suddenly felt like I enjoyed it and now I feel really scared and disgusted in myself and I might have been thinking it because I genuinely wanted to and enjoyed it even though I feel awful now

Recently I’ve been having scary intrusive thoughts about hurting myself or others. I’m so scared, what do I do?? I wouldn’t hurt a fly.

This may upset some people reading so here is just a warning that these are disturbing I don’t know what to do to make the bad thoughts stop. My mom recently had a baby, my little brother. I wasn’t exactly happy about this pregnancy, but I have nothing against my brother. He’s adorable and silly. Nothing against him. But I feel like these thoughts bug me because what if deep down I do resent him because I didn’t want my mom to have another kid? What if I did act on these things because I hate him? What if I just lose it and do something? It’s all so illogical, I know. Never would I ever want to do that. But there’s times I’m watching him for a few minutes for my mom and my brain just shows me an awful scene of me brutally hurting him or killing him. Or I’ll be holding him and my brain shows me a scene where I purposefully drop him or I just hurt him so badly. I’ll be walking near him and my brain tells me I’m going to stomp on him. It shows me such bad things. I have intrusive thoughts all the time, but this is different because there’s a semi good reason I “could” do it. That being, I wasn’t happy about the pregnancy. And it scares me. I’ve started crying because I was so scared it was going to happen. I have to back up away from him or sit down so there’s no way I can do anything. I feel horrible. I don’t want to hurt him. And I’m so scared I will. But I won’t. I’m hoping this makes sense to others who struggle with this. Because to anyone else who’s never gone through these things I’ll sound insane. And sound like a psychopath. Thanks for reading. Any help would be appreciated.