You may have conditioned yourself to be cognitively sensitive to jolts and replay the memory of your concussion as if they are real. This is an anxiety response.

The symptoms you list are not concussion symptoms in the context you note. Nausea and dizziness are not symptoms of a mild concussion. They are symptoms of a true bell ringer concussion. You did not suffer a concussion, much less a bell ringer concussion.

Those symptoms are all symptoms of anxiety.

You don't mention anything about your concussion cause or time.

Every head impact effects the neck. 80% of concussion symptoms are neck related. The subtle neck strains cause inflammation.

So, you need to work on healing yourself. Rejecting any thoughts of such an event being a risk is important. It only takes one thought, even a doubtful thought, to trigger symptoms.

The mind is very open to suggestion, especially during stress.