I've been away a while and have missed many posts I am sure, but I am sorry that it sounds as if little has changed at home...
How is your dad dealing with all this? I don't remember you talking much about him.
You do matter. I hope it won't be long before you can get out of the house and find support, new interests, and time to heal and gain your own perspective...unfortunately it seems your mother is comfortable in the place she has isolated herself...------do you and your sister have a good relationship? ...and, do you have someone to talk to?