I am afraid...

I am afriad of death, i just dont know why but me thinking that im gonna die one day is scary. I wunder what happens when that day comes. Will I'll just sleep for ever? Will I just wake up in another world? Who knows? I think that is one of my biggest fears. I would like to know where do people go when they die, is it really to hell or heaven? If its heaven how dose it look like it? What do you feel? and if its hell then....what happens there?