Wow. I have only just seen this thread and have read it from start to finish.
Living, I've had that feeling of... Dislocation. Feeing separate and as though I was no one. It was combined with a period of immense stress in my life.
I see it as your brain creating a buffer zone for you. It's all too much sometimes, there's too much for your brain to process and deal with, and so it steps back from everything, so that you can keep functioning and not have to deal with a multitude of feelings all at once.
Usually, given time and space you can recover and slowly your brain takes on more, as it has rested, and you regain that feeling of connection and being a part of the world.
But because you don't have the respite you need, because you haven't got the time to stop and heal, because you have to keep going and there is no end in sight for your stress, it's all ongoing.
And you're trying to find a reason for this disconnect. The reason you've come up with is that you are in some way evil, a non-person, somehow lacking in a way that other people aren't. That's where those thoughts come from.
But here is the truth (and the truth is quite the opposite), you are functioning, and continuing to function when most people would have broken and buckled. Your brain is doing its absolute best to keep you going, and it's done an incredible job.
I like analogies, so here's my take on it: life fractured your leg. You didn't have time to stop and let it heal, so you stuck a splint on it, grabbed a crutch, and hobbled on. If you had some time to sit still it could heal, but you don't have that time. every day you walk on that leg, but you don't want to complain and burden other people, so you decide the problem is you. You should be able to run. You are angry with yourself for not being able to run.
Ok, it's a silly analogy :)
You are still there, and you are whole. You are a whole person. You're just in survival mode right now. Your incredible brain has shut down some functions so that it can keep going. It's a kind of burn out.
I read how you deal with your son, your hopes for his future, and your disappointment in your family, and your love for him shines through. It is so very clear in how you speak about him. Your love and admiration for your dh too. There is no evil in you. There is strength and there is love, and you are having to cope with so very very much.
You need support, you need counselling. You maybe need a new GP who prioritises your care.
You are amazing.
You are more a person than the vast majority of people!
You are so very strong.
You are also in the hardest bit right now. Hold on.
Could your dh come with you to the GP with you, and stress just how much you need help?
Christmas? Do what is best for you and dh. Put you and him first. Forget any "family duty". Pull together.
for you.
I hope my ramble made some semblance of sense.