Hello. Unfortunately I can't say I can relate or know how to interact with the issues you've listed. The rest of my post will just be me asking questions, few suggestions and an opinion. You're free to ignore it since it's not exactly what you asked for.

Have you tried seeking proffesional help? If yes, and it hasn't worked out in the past. I'd say, keep trying. I don't have personal experience, but many who do with seeking prof help say that sometimes it's about finding the right proffesional.

I can see for myself, why i wouldn't open up to those who don't understand. So perhaps if you haven't already, just keep on sharing your story on forums and sites until you eventually find someone that can relate. I'd also personally use the copy and paste function. Something else that could be done, if you haven't already, is to address each issue you listed individually. So perhaps finding a community, forum, etc specializing or centered around BPD, then Complex PTSD and so forth.

Laslty, i don't know if those around you have made you feel like your a burden to them, or if you simply feel like a burden regardless. But the people that end up staying your life. Who knows, they might feel that way. Or they might not see it like that. But they made a choice to stick around because of you. For whatever that's worth.

And of course, if you're ever feeling that way when you post online. Remember that the people that respond to help, choose to do so.