am i going to die?

i always have the feeling like im about to die. i dont know if ive written about this before on here but it just bothers me so much. every night before i go to bed im scared im going to die in my sleep, when i go out with my bike im scared ill get hit by a car or something, whenever i enter a car im afraid itll crash. i dont know how to stop thinking about it. i keep thinking that maybe its a sign, which gets me thinking about death itself. it really does feel so close. im not suicidal by any means, im having a real good time, actually. i just feel like its about to end any day now. i get paranoid about every little thing on my body, ever since ive had cancer i keep thinking itll come back and maybe i wont survive it this time. i dont know if id regret my life if i died tonight. ive done everything ive wanted to, everything i can think of off the top of my head has been done but then again ive never really had big goals to begin with, so maybe having fullfilled all my wishes doesnt mean much. i start charishing things alot more. the smallest things like a pretty colour or a cat on the street get me so emotional nowadays. im feeling nostalgic about something thats still around. its like im an elderly woman on her death bed reminiscing about her youth, even though im still in it. maybe this is a sign from the universe? or is this a common thing? its bothering me alot, its like a stain amidst perfection. everything this year has been going amazing, except for this one thing. maybe im jinxing myself by writing this. i hate telling stuff like this to my friends or family because i dont want to worry them with 'oh i have the feeling that im about to die'. ill just seem dramatic to them. its not a concrete problem, is it? i always read stories about people my age or even younger dying. whats the difference between me and them? the chance of them dying is just as high as mine. i just feel weird that THEYRE dead and im not. and im not even talking about people i know. just random other 15 year olds. i feel weird going on with life knowing that some other person who was exactly like me wasnt able to do the same. sometimes the feeling doesnt bother me, other times it makes me cry within seconds. i dont know what to do with it.