Has anyone else here gone through a period where you genuinely feel like you aren’t the same person you were before?

I’m at the tail end of that phase right now and I think I figured out why it happened, but it’s the most frustrating of hopeless situations. I felt like I wasn’t even in the real world anymore, I was just living in my own head and watching the days go by. My entire existence consisted of worrying about who I really was, what I should be doing, what I’m missing, what I pay too much attention to, the self-doubts just wouldn’t end. You want to help get yourself out of that mindset, but YOU are the problem in the first place! I feel in those situations you’re at the complete mercy of those around you and random happenings in your day-to-day life, it’s all you’ve got left when your own mind turns against you. If you don’t have someone to smack some sense into you, and you aren’t relying on the outcome of some sort of upcoming event, climbing out of that mental hell you’ve fallen into is nearly impossible.