I walked into the corner of a low-hanging, plaster-on-brick doorway at a slow-to-medium walking speed -- which is about 1.0 to 1.5 m/s. The corner made contact with the top-front of my head, about 2 inches back from my hairline -- the middle of the frontal bone. Despite a shooting pain that resonated in my teeth there were no noticeable immediate symptoms, and the fact that I stayed on my feet and experienced the full arch of the pain means I didn't lose consciousness. No amnesia either (pre or post) Despite being quite sharp, the edge didn't split my scalp but did produce a raised welt.
The problem is that I had only had about 2 hours sleep that evening, and therefore felt understandable tired throughout the day, but being prone to anxiety -- as you accurately judged -- I am worried that my mental slowness wasn't entirely the result of a lack of sleep.
As I mentioned, I have heard cases were people suffer an impact and then only develop symptoms hours or days later. Is this just something medical professionals say to make sure people are not complacent, or might it result from the fact that many sports people do not take the immediate symptoms seriously, because they often resolve quickly without any long term problems, or hide them to stay in the game -- and it is in these cases that the symptoms can come back later?
I don't have any diagnoses per say, but I am prone to episodes of profound and long lasting anxiety. I can be fine for years (even show slightly reckless and fearless behaviour) and then some type of negative thought process gets going and I become a nervous wreck. I have an obsessive mind. I talk about the same subjects again and again, and have done well academically because of this. (Do not register very highly on the autistic spectrum though).
I had an SWI scan and it came back perfectly normal.