Hi Carpediem46,
I understand how you're feeling.. but im also in the transition phase here so I dont have much advice for you..but.. You're not alone.
The way your family treats you is their way of coping and its really destructive and abusive and its not fair. I also have PTSD and DID because of my parents. They act as if nothing happened though so its hard to get better, but enough about me. You need to know that what happened to you as a child was out of your control and that what you're dealing with now are the coping mechanisms that your mind came up with to help you live. It's hard to un-do the damage they've done.. I know..
You're not a burden. You're hurt and you're scared.. and your family seems to be taking the pressure and guilt off of themselves by dumping it on you. The fact that you're here, however, shows how strong you are and that you can make it through this.
You sound like such a sweet and caring person.. I know you are and it's not fair that this is happening to you.
I'm so glad to hear that you have a therapist that understands you and helps because it's real hell without one.
I still feel like a burden to my family, to the world.. but i think that's something you and i will always feel until we can prove to ourselves that we're worth something.
This wont sound like much, i know, but I DO understand and give you my support. If you need to talk.. you can come to me

Something else that may help.. is the idea that you can almost rebuild your family.. because your parents are sometimes just biological parents. You don't choose them. But you can choose and find good friends and they can become a loving family for you and make up for what you never had.
You have to be very careful though (this is a big struggle for me) do not to try and look for new parents.. ( i know that sounds almost contradictory to what i just said .. im sorry) You may not have a problem with this, but even though im now 20.. i look for substitute parents in authority figures and supportive adults. its really bad and isn't fair to them because its not their responsibility.
I'm really off topic here..ahh, im sorry.
Nathan really wants to talk, but I'm hesitant to let him do so.. thats why we/I'm not making much sense right now.
Anyways, you're a beautiful person. i'm happy that you're looking for help, keep your chin up

things will get better.
You might find that you will develop or maybe you already have an alter who represents your mum.. and the way she treated you. or maybe one of your alters treats another the way your mum treated you. Or you will treat one of your alters the way you were treated. If you experience this.. you need to do one thing: be compassionate to them all. Because thats your way of fighting your mum/family. Its an internal battle, but you need to forgive them so you can move on, and your alters are part of you, so you need to love them..
i've probably said too much about things that aren't even relevant.. so i'm sorry for that.
I hope that at least one of these sentences that i've written will prove to be helpful to you.
I wish you the best of luck and I pray for you.
<3 take care.
-gloria (with nathan on the border).