Time will help. But given your background (lots of experience) and the extent of your fear (pretty extreme) I would see a sports psychologist. Many, many sports professionals do. Many sports teams have psychologists on staff (e.g., even big strong football players have to work through fears or performance anxiety). I wish I'd seen one right away when I was in a similar situation.
Fear is a very real thing. Overcoming that is a process that each of us has to go through differently, as we process life's fears/accidents/tragedies all in different ways, based on our past history, our genetics and our environment. My recommendation is to get with a good therapist who understands and works with athletes. Just to have someone to talk through this with and how you are feeling. Better than all these pop psych suggestions on this forum. They can listen to you and respond with some very real suggestions to get you to put this in a perspective that you can deal with and move on from. The thoughts of that accident will always be there--it is how you allow those thoughts to dictate your future actions that you have to come to terms with.
Discipline is the Bridge between Dreams and Accomplishments
A few points for the OP:
Riding is not like driving. Riding is a selfish thing we do. Driving is usually something we do because we have to get groceries, get to work, kids to school, etc. It's a necessity for many of us. Getting hurt feeling selfish brings with it guilt, errands are not a guilt producing activity.
No one can say for sure you'd have died w/o a helmet. We like to speculate, but NO ONE can truly say that. Let that "danger" go from your brain before it feeds more fear.
Decide if your responsibilities in life (family) would be happy with you if you gave up your passion for horses. If you quit riding for you it's one thing, but if you quit riding for others it can grow in to resentment, and that isn't a happy person to be around.
Go to the barn, stay home and heal, do whatever feels right for now. If you start looking for reasons to not ride it might be time to see a BH person. BW, I am another with several accidents in my past. Roughly 17 broken bones, four major surgeries, lost count of the number of stitches & concussions. Injuries remind me I am mortal, and my hobbies remind me I am alive.
^Isn't that the sad truth! And, even the bed isn't safe - I'm thinking of that poor guy sleeping in his bed in Florida who got sucked down a sink hole -- and his poor family
I went through the wondering if I should continue riding thing after a couple of minor injuries from falls. Same thing with the responsibilities, husband, children etc.... Well I was on my back porch slipped on the ice and received a closed head injury. All of my horses and other great ways to get injured at home and I slip on ice. You have to do what is best in your mind. After I came out of the hospital I felt like you should wear a helmet 24/7. I don't ride now but I do have a Black Forest Horse for driving. I thought driving might be too boring but it is a blast! Lots of things for you to consider. Take time to heal and go slow.
It's not true that I had nothing on. I had the radio on.”
? Marilyn Monroe