I have allways been XXXXtremly easy to startle.
Like this:
I am on an elevator and the doors open up and if someone is standing there, I scream.
If someone comes up from behind and says something, when I am not expecting anything, I scream.
When I am a passenger in a car I am Constantly jumping and freaking out, to the point of crying. I keep thinking that we are going to crash.
Once in the summer time, while I was a passenger in a car, we drove over a brige that had a sign that read " watch out for ice on bridge" and I about had a heart attack.
If I have a bad dream I wake up crying.
It is instinctive and primal. I am usually the type of person that is not afraid. Like I will not lock my door if I am home etc.

DIAGNOSES~IS THE TERM FOR FALLOWING UP ON SYMPTOMS

U HAVE TO HAVE THESE COMMON FIGHT & FLIGHT THINGS AS IT IS IN YOUR MAKE-UP TO OVER WORRY, SOON IT WILL TAKE ITS TOLL ON YOU AND YOU WILL BE WORN DOWN TIL YOU NO LONGER HOLD THIS ATTITUDE AND U CAN DIFINE YOUR CONTROL IN YOU BETTER, WHEN THESE FEAR ARE UNFOUNDED AND DO NO GOOD TO YOU, THEN YOU'LL ENDURE THE CHANGES OF YOUR CONFIDENCE AND LESSON THE TRAMA OF ADJUSTING YOUR SELF AND BEGAIN TO LIVE IN YOUR SELF, WITH OUT THESE NAGGING EMOTIONS, WE GROW AT OUR OWN PACE

Generalized Anxiety Disorder. Anything causes anxiety. See yourpsychiatrist-he/she can prescribe meds for that. You'll be fine.

I think that your self-knowledge, illustrated with examples, and your characterization that it is "instinctive and primal" is very good to this point, and now rather than doing more self-exploration in searching for the medical term, it is time to carry what you have in partnership to a worthy therapist, and a psychoanalyst, if affordable, the latter because of its primal nature. What I do pick up is that you so clearly state that when you are not in control (not at the wheel) of a dangerous activity such as being a passenger, it is almost impossible for you to trust someone else and that fear is compelling. the same with an elevator. You are usually not afraid, and that is why your fear of startle can be remediated well with help. the splintered primal problem can be helped by someone traveling with you down the primal path, possibly beyond the realm of your present consciousness. as to the bad dreams, many of us wake up with the impact of the same upon us, and the more sensitive don't necessarily shake them right off.

Post Tramatic stress disorder with panic attacks