Just because you can't do the sport anymore doesn't mean you can't be part of it in other ways. Maybe pass your knowledge on by doing demo videos, organising competitions or get a teaching qualification and train teachers? It's great to be into something and belong to a group but it can give you tunnel vision a bit. Like Bezelbore92 I used to live and breath skateboarding as a teenager and sustained 2 concussions which probably contributed to my PCS when I bashed my head last year - it's certainly made me look at life a different way.