Keep having nightmares about losing my wife in a car wreck and i am distancing myself from her....?

My wife and i are newly weds and we are both 26 years old. Well lately i have just been very distant from people and just wanting to withdraw and i do not know why. And i keep having nightmares about my wife being in a car wreck and getting killed and so it is really starting to bother me and such =/. To the point it is making me withdraw and distance myself from her. I know it might be i do not know what its just if i lose her i do not know what i would do with myself. Well she has started to pick up on it and has started to get extremely overprotective and overbearing thinking i am going to do something to myself. I don't know how to tell her i am trying to distance myself from HER. I don't know how to tell her about these nightmares and everything. Because i am so scared of losing her not sure what to do. Advice?