To dream of death and dying might indicate some health issues you are concerned about.
It could also indicate you might be feeling threatened by some situation in your personal or professional life. These types of dreams seldom represent reality but rather a metaphor - think about a situation that seems to be coming to an end.
Or perhaps you feel a chapter in your life is closing - end of school, another person entering into a relationship you have with a close friend, etc... Death or dying as a symbol of another event is the key concept to consider.