I don’t share your conclusion that you wouldn’t profit from professional help. Boredom and laziness are not typically viewed as the source of killing fantasies. By your own reflection these fantasies don’t make sense if you score high on psychopathology and yet can also feel genuine empathy. Since you are interested, I’d recommend adding to your efforts at self-diagnosis with at least an initial interview with a clinical psychologist or psychiatrist. He or she can offer you some ideas about what might be going on — and perhaps more importantly, what can be done to help reduce these intrusive thoughts. You university’s counseling center should have some qualified people you can talk to.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral