derealization is indeed a very unsettling symptom, but please know that it's completely harmless. when your brain is overwhelmed with stress, it sort of "shuts down" so that it can take a break and detach itself from the current stress going on around you. that explains why we feel disconnected from the world when we get this. i had derealization for months at a time once because i kept obsessing over it, consequently adding more stress onto my plate and prolonging the unreal sensation.
the best thing to do with derealization is to just let it run its course. i know it's very difficult when it feels so scary. there's nothing worse than not feeling like yourself, not feeling "there." but give it time, and it will pass, i promise. this is a very common symptom with chronic stress and anxiety so you're definitely not alone in feeling this. if you think of it as your brain's defense mechanism to keep you safe, then it takes a little bit of the fear out of it. knowing that is what pulled me out of the derealization and feeling like myself again, and i know you'll pull yourself out of it as well.