I very much doubt that extra knock would have done any more damage. Once injured, the body tends to go into a nursing phase in which the injury is both thought about and guarded in a very over enthusiastic manor. Part of the self preservation instinct, no doubt. Obsessing over a head injury is easy and tempting. The more you give in to that instinct, the more your brain will conjure up feelings which are lies and thoughts that are doubtful and negative.

The negative spiral of pcs can be your biggest hurdle to feeling better. That's not to say your injury is imagined, it is to say that your injury is made worse by obsessing over it.