What you experienced is called sensory recall. The brain gets triggered by the visual, maybe sounds and smells of the new event. This can also trigger some of the emotional trauma. This is sort of like PTSD.

There are therapists who can help you with it but since your injury was from a voluntary action, the therapy will be more difficult.

It is difficult for me to understand all that you have posted because you appear to be attempting to use sarcasm and such to describe what happened. The concussed brain often has a difficult time sorting through sarcasm and other indirect comments.

I don't think your flashback concerns are the biggest issue you have. Getting back on the track and subjecting your brain to further injury is a much bigger issue. Your next head impact will cause more damage from a less intense impact.

You might benefit from a sports/performance psychologist. Your reactions will be effected by your injury and these flashbacks so you need to seriously consider the risks.