I am sorry that you are in such an acute state of DPDR. I have been there, and I can identify with everything that you said. And I can tell you that I got better, a lot better, but I had some painful trauma processing to do before I recovered. Well, I still am recovering, but I am miles away from where I've been almost four years ago...Hopefully, it does not have to last that long, and sure, I had ups and downs, not being constantly DPd, or at least not to the same extent...sometimes it would get better, and then I would have another layer of trauma processing to do, then would get better, then encounter another one, and so on...I only mention trauma processing, because grief processing is also a complicated and hard thing to do.
What caught my eye in particular in your post is the guilt that you feel for not being the person you think you should, or that people around you need you to be. I had a lot of that too. However, I soon realized that I need to do whatever necessary for me to recover, and in order to recover, we cannot feel irrational guilt for things that are out of our control. And we need support of our close people, and we need to feel secure in those close relations, and also not to be ashamed to ask for help, because the state you are in is not your whim, it is a state of a deep hurt, and it is as real as any other health issue.
I cannot give you advice on how to handle your recovery. I had some CBT, and meds, to stabilize me when I felt the worst, but also a lot of support irl, then I found support in self-help groups online, and in general I looked for help wherever I could, and also I wrote a lot, every day for myself, and from time to time I posted about things that bothered me, or about some breakthroughs that I had. I don't think it is ever one thing that will get you out, but rather a network of things, in particular those things that don't let you isolate yourself even more. Meds come in when person is in such an acute state of panic that she has to be stabilized first in order to get somewhere. In this respect, meds helped me when I was a mess, but then again, I don't know what the outcome would be without them...
Would you perhaps like to share as to why this particular video killed your hope?
I am suffering from depersonalization-derealization disorder, and I am diagnosed with it, as a disorder on the spectrum of dissociative disorders. I haven't got it from drugs or (for most part) anxiety, but from a prolonged childhood abuse that I suffered, and in my case it is completely trauma-related. It means that I cannot just solve it by relieving my anxiety, even though relieving my anxiety helps, but that I have some other background issues to tackle. It does not mean that I am doomed with this disorder, it just means that my path to recovery is somewhat more complicated - but not impossible!
I have to say that I see nothing wrong with what this guy is saying. He allows for other possible causes of depersonalization to exist, but he is pointing out to what he suffers from, and that is what he is mostly talking about through his channel, from what I understood, based on this one video. It does not have to refer to you. Also, you should only rely on a good therapist to tell you what you suffer from, and by no means assume on your own what kind of DP do you have.