I graduated nursing this past december and just found out today I passed the NCLEX so I know all about the struggles of nursing. In reality, patients are going to die, all you can do as a nurse is do your best to prevent that from happening, or to provide comfort till it happens. My first day in the ICU department during clinical a patient died on me. I was sad, obviously, but i knew i did the best that i could. Anyway, nursing school is HARD, and it's meant to be that way. Now that I'm working I know that nursing school prepared me for the worst, but it really does get better afterwards. I had a few friends that doubted themselves, but eventually they realized it was from all the stress of school. Just think about if this is what you want to do for the rest of your life, and if you really REALLY don't want to do it, don't do it.
Wish the best for you!!!