Does this happen to anyone else?

I get this too but most of the time it isn't other things hurting myself it is like, me hurting myself. I also have wondered why this happens and if it could be a bad thing. Like if i see something sharp I'll think, what if I would just grab that and stab myself or if I'm by a window I think, what if I would just jump? You know, stuff like that. Anybody else know the answer? I just though you might like to know you're not alone!