Passing out or loss of consciousness is not necessary for it to be a concussion. Many concussion symptoms do not manifest for days to even a week or two. A concussion is a process, not a single moment event.

Prolonged headaches and the rest is symptomatic of a concussion. For some (me for one), the prolonged headache can become chronic and last for a few months.

Anxiety can cause memory difficulties. Nobody can easily diagnose whether it is from concussion or anxiety.

It would be best to keep your questions in one thread. That way, we can scroll back to see other comments and issues. Don't worry about your question not matching your thread topic.