well, when i was taking abnormal psychology, my teacher said it is perfectly normal to have the thoughts of jumping off a bridge or driving into oncoming traffic. these types of thoughts just pop automatically into our minds. lots of struggling people will automatically have thoughts of self harm. i think these are along the same vein my teacher was talking about. so the thoughts you are having could be perfectly normal if they just come randomly on occasion. however if they are constantly on your mind and you are having trouble fighting them off and you find them disturbing, then you may want to seek help for them to get to the root of the matter.