When I have a lot of time to myself, I start my imagination starts wandering, and running these crazy, sometimes dark scenes through my head. Often they involve family or loved ones. I have no desire what so ever to do these things or want them to happen in any way shape or form. Is my imagination just getting the best of me, or is there something more sinister going on.

You should probably talk to a counselor about this. I also feel like if you get involved into activities to preoccupy your time your mind would move on from these thoughts. I don't believe that something sinister is going on but you might just being over thinking trying to stop yourself from thinking about something which leads you to thinking about something. I also think it would be a good idea to enjoy spending time with your family and expressing love toward them which might get rid of those thoughts.