My first thoughts after reading your post OP were that you are very young and do you want to be fearful the rest of your life? No, I am sure you don't. I started being afraid at an early age of having a heart attack, it stayed with me for a long time, but eventually went away until recently. I wasted many years over a non-existent threat.

Try to realize, which I do know that 99.999% of your fears are NOT going to come true. Really! I am 59 going on 80 from worrying myself to death, I inherited the habit from my parents plus add in my own pathology. I studied the human body, worked in cardiac units of hospitals and came to realize that my fears were ridiculous. Unless you are born with some genetic malformation, or you take drugs or do something to harm yourself, most likely you are not going to die anytime soon.

Both your of symptoms are obsessive thoughts and probably stem from depression and anxiety. If you can get some therapy and find a way to stop the obsession over dying and the functions of the body it may help. You are a living, breathing human. If you did not have all those bodily functions, you could not live. It may not be pretty on the inside, but who looks at that regularly? Maybe a surgeon. I used to see it all the time but the key is that I did not obsess over it. You are not a mannequin. You are alive, just like all creatures in the universe. Those are irrational fears=they have no basis in reality, not rational.

I hope this helps, I know all about the obsessive thoughts and truly empathize with you.