sick thoughts

Am I alone in obsessing about hurting myself?  When I'm at work my mind constantly revolves around killing myself.  I have a rude customer and I want to end it.  A customer touches me, just in handing me money, and I cringe with disgust.  I look around at all the people shopping and all I can think are horrible thoughts.  I wish they were all dead.  I wish there was an apocalypse and most of the world died.  This is not healthy.  I'm only happy at home.  If I never had to leave my home I would be in heaven.  Once I start thinking about hurting myself, whether it's cutting or suicide I end up obsessing for days or sometimes weeks.  I know the name for it- suicidal ideation but that doesn't tell me why I do it.  It drives me crazy.  I truly wish I could move somewhere rural and I could work from home and then I could decide when I have to deal with people, on my terms.  Someday, hopefully.