Invasive thoughts?

Hello, so my family does not believe in mental illnesses, so I’ve never gotten the chance to speak up or seek a professional. I’m very new to the subject. What are invasive thoughts? I often have daydreams about myself or my family going through disasters, like a tree falling on my house and killing us, or being mass murdered. I also when I was very young would daydream about carving my freckles out of my skin with like a knife, not to hurt myself but to just get rid of them. I don’t know if this is normal. It doesn’t bother me where I’ll get anxious or panicky but it really does upset me. Should I seek help?