Welcome to HCM
We understand your concerns
I went through your problem description. I suggest you not to worry too much. Concussion
occurs after a blow on the head. Delayed concussion syndrome is manifestation of some symptoms some time after the actual blow. A syndrome is combination of several symptoms.
As you had a blow which is mild, you may not have to worry. Also, the doctors would have told you if there is anything wrong. The symptoms could disappear within a week or so. It could depend on the severity of the blow. But there is nothing to worry. Be positive.
Hope this clears your doubts. Available for further clarifications.