I had terrible pressure in my head for a long time and at 17 months out still get it.

The pressure was there even just sitting and when I walked it got worse, I'd actually walk along holding my head.

I might be wrong but I always thought the pressure was a common symptom of concussion.

The not thinking clearly is common too, I couldn't get words out properly, think properly, couldn't read for 5 months...it took time but did improve, not 100% by any means though on the thinking clearly and have to think hard sometimes for certain words.