Karlin, I'm sorry that you're feeling that suicide is the only solution.  You asked 2 questions:  "Am I being reasonable," and, "Why did the car shut off"

I believe that you can provide the answers to each of the questions, yourself.  I cannot objectively determine when suicide is "reasonable."  I have been taught through various avenues (including holistic medicine, and my own epiphanies) that there always exists hope and reason to live as long as there is breath in the lungs.  As far as the car shutting off, again, I cannot begin to explain what happened, as I wasn't there.  You are more likely to determine what happened better than anyone else.  Sit with it.  Think about it.  Contemplate.

My personal view is that we are not given the choice as to when we enter this world, or what cards we'll be dealt in our hands.  For me, personally, suicide has been an "inviting" solution to my many, many issues, pain, and conditions, but I've learned that even suffering has a point, and I'm not going to get into that discussion, here.  Suffice it to say that it's final.  There's no reset, there's no do-over, there's no taking it back, and the people that we would leave behind will be tortured by our actions, regardless.  

Since you've already attempted a suicide, it might be time to contemplate a different route.  Please, take time to visit the following site for some answers, suggestions, and hope:  https://suicidepreventionlifeline.org/

There are many things in this life that are still beautiful, even in the midst of my pain and physical misery.  I take time, each day, to remember what those things are and that I am not going to let anything beat me down, today.  I cannot predict what will happen tomorrow, and yesterday is done.  Just for today, I'm facing Life, as it happens.  

I wish for you the very brightest blessings of comfort and healing