I experienced depersonalization episodes as a kid. It wasn't quite what I'd call "really bad" (meaning, I wasn't too distressed over it), but it happened all the time. It was at a point where I'd even learned to take advantage of it and autopilot my way through certain unpleasant tasks.
In high school, I took up competitive running, and the episodes simply never happened during workouts or races. I think the key mechanic there was that when I was strenuously exercising, and continuing to push myself harder through the pain, it just became impossible to deny the realities of my existence and my agency.
So running played a helpful role for me, and you might consider taking up strenuous exercise if you haven't already. Curiously enough, I largely "grew out" of the depersonalization episodes, and they've been an extremely occasional thing for me in recent years.
