Thank you for posting this. I'm sorry you are having so much difficulty. I can relate to quite a few aspects of your post (even if to a somewhat lesser degree.)

You wrote you hoped someone might offer some ways to help; and unfortunately that's probably not going to be me. In my own case I've simply come to the point where I've decided things are as they are and that's the way it is. I've given up trying to find solutions for my own mental health problems. It's cold comfort, I guess. But there is also a certain serenity in simply no longer fighting it. Perhaps it's easier for me because I'm old and don't have all that many more years left to worry about.

There are a few little things that seem to help me day-in and day-out. Routine is very important to me. I basically do the same things, in the same order every day (with the occasional necessary exception.) I don't have a formal meditation practice. But I pay attention to my thoughts and feelings as the minutes, hours and days pass; and I try to take note of things I find disturbing or that seem to aggravate my anxiety level (which I at least believe is at the root of depersonalization / derealization.) And as I identify things that tend to aggravate my anxiety level, I make a point of avoiding them as much as possible. For example, watching or reading the news is one thing that aggravates my anxiety level. So I minimize the amount of news I expose myself to. I also allow myself to indulge in practices that others might find... shall we say... a bit weird but that comfort me. (I have actively self-harmed in the past.) They're practices that don't harm me. But they are, for me, something akin to grounding techniques. (I'll spare you the details.) I also listen to a lot of very calm quiet music... never anything loud and boisterous nor do I watch TV shows or movies that contain gratuitous violence. (If I start watching a show where gratuitous violence shows up unexpectedly, I turn it off. (I'm also on 2 mg. per day of Clonazepam, by the way.)

I don't have a formal diagnosis although I've been kicking around the mental health system where I live for over 20 years now. And, over time, I've come to believe that mental health diagnoses are simply the opinions of the particular mental health professionals one happens to see. And if one sees 3 mental health professionals one is likely to get at least 4 different diagnoses(!)... because they're just personal opinions based on what each mental health professional happens to know about you; which probably isn't all that much when compared with the totality of one's life experience. So, as a result, I personally don't put much stock in mental health professionals. I guess they are sometimes helpful to some people... perhaps even critical in some cases. But whenever I suggest someone here on MSF see a mental health professional, I always have this little voice in the back of my head that tells me: "a lotta good that'll do.) I do see a psychiatrist for about 5 or 10 minutes every three months or so simply for medications management.

Anyway... probably nothing I've written here is going to be of much help. Perhaps other MSF members will have beneficial suggestions to share. But I do hope that, in some way, you can find a path to inner peace. My best wishes to you...